Idioms are special figurative expressions where the words together create a meaning completely different from what they say individually. People use them in everyday speech to make their descriptions more colorful, vivid, and memorable. In this article, you will learn fifty unique idioms related to fake friends, betrayal, and untrustworthy people.
In this lesson, we’ll look at idioms that mean false friendship, backstabbing, and deceit. Let’s get started and explore some of these helpful expressions.
Idioms for Fake Friends
1. Act like a friend
Definition: Pretending to be supportive and kind while actually having hidden selfish motives.
Used in a Sentence: She would act like a friend at school, but then spread rumors behind my back. / Don’t let someone who only acts like a friend trick you into trusting them with secrets.
Similar Expressions: Pretend to care / False kindness
2. Add insult to injury
Definition: To make a bad betrayal or hurtful situation even worse with mean remarks.
Used in a Sentence: Not inviting me was bad enough, but laughing about it added insult to injury. / Losing the election hurt, but hearing my supposed friend mock me added insult to injury.
Similar Expressions: Make matters worse / Compound a betrayal
3. All talk and no trousers
Definition: Someone who makes big promises about loyalty but never actually supports you.
Used in a Sentence: He promised to back me up in the debate, but he was all talk and no trousers. / Don’t rely on his big promises because he is all talk and no trousers.
Similar Expressions: Untrustworthy boaster / Empty promises
4. Apple of discord
Definition: A person or issue created by a fake friend that causes bitter arguments.
Used in a Sentence: Her gossiping became an apple of discord among our group study partners. / Spreading those false rumors acted as an apple of discord in our friendship.
Similar Expressions: Cause of dispute / Bone of contention
5. At daggers drawn
Definition: Being in a state of open hostility after a fake friendship falls apart.
Used in a Sentence: Once everyone found out he lied, the former buddies were at daggers drawn. / After the betrayal, the two classmates were at daggers drawn in the hallway.
Similar Expressions: Bitter rivals / Hostile enemies
6. Back-alley dealer
Definition: A sneaky, untrustworthy person who makes shady deals behind your back.
Used in a Sentence: You cannot trust someone who acts like a back-alley dealer with group project notes. / He traded our ideas behind our backs like a back-alley dealer.
Similar Expressions: Sneaky operator / Shady person
7. Back-seat driver
Definition: A fake friend who criticizes your choices from the sidelines while offering no real help.
Used in a Sentence: Stop acting like a back-seat driver and criticizing my art project when you didn’t help. / Nobody likes a back-seat friend telling them how to run their life.
Similar Expressions: Unwanted critic / Sideline meddler
8. Bad egg
Definition: A dishonest, unreliable person who brings trouble into a group.
Used in a Sentence: The teacher realized that new student was a bad egg after catching him cheating. / Stay away from that bad egg if you want to keep your reputation safe.
Similar Expressions: Dishonest person / Troublemaker
9. Bark up the wrong tree
Definition: Accusing or trusting the wrong person because of deceitful behavior.
Used in a Sentence: If you think your true friend stole your notes, you are barking up the wrong tree. / The liar tried to blame me, but everyone knew he was barking up the wrong tree.
Similar Expressions: Blaming the innocent / Misdirecting trust
10. Bite the hand that feeds you
Definition: To betray or turn against someone who has been kind and supportive to you.
Used in a Sentence: Spreading rumors about the classmate who helped you study is biting the hand that feeds you. / Never bite the hand that feeds you when friends share their lunch or notes.
Similar Expressions: Betray a helper / Act ungrateful
11. Blank slate facade
Definition: Putting on an innocent, blank expression to hide sneaky or deceitful actions.
Used in a Sentence: He hid his dishonest trick behind a blank slate facade when the teacher asked questions. / Don’t trust her innocent facade when she pretends she didn’t ruin your poster.
Similar Expressions: Innocent mask / Hidden deceit
12. Blow hot and cold
Definition: Changing your attitude toward someone constantly, being friendly one day and mean the next.
Used in a Sentence: She blows hot and cold, acting like my best friend at lunch and ignoring me in gym class. / It is exhausting trying to maintain a relationship with someone who blows hot and cold.
Similar Expressions: Unpredictable friend / Moody behavior
13. Bolt from the blue
Definition: A sudden, shocking betrayal by a trusted companion that you never expected.
Used in a Sentence: Finding out my best friend leaked my secret diary felt like a bolt from the blue. / His sudden mean rumor about me came like a bolt from the blue.
Similar Expressions: Total shock / Unexpected betrayal
14. Bone of contention
Definition: A persistent disagreement caused by a deceitful person’s actions.
Used in a Sentence: Who started the cruel rumor became the main bone of contention in our club. / Their untrustworthy behavior remained a constant bone of contention.
Similar Expressions: Source of argument / Core dispute
15. Break faith
Definition: To break a promise of loyalty and betray someone’s trust.
Used in a Sentence: Sharing my personal secret with the whole school means you broke faith with me. / True companions never break faith when entrusted with confidential thoughts.
Similar Expressions: Break a promise / Betray trust
16. Burn your bridges
Definition: To permanently ruin your friendships and reputation through dishonest actions.
Used in a Sentence: Lying to everyone in your study group will completely burn your bridges. / Backstabbing your teammates is a fast way to burn your bridges at school.
Similar Expressions: Destroy relationships / Cut off support
17. Cast aspersions
Definition: To make malicious, untrue remarks about someone’s character behind their back.
Used in a Sentence: He tried to look cool by casting aspersions on his supposed friend’s artwork. / It is cowardly to cast aspersions when the person isn’t there to defend themselves.
Similar Expressions: Slander / Speak ill behind backs
18. Chameleon character
Definition: Someone who changes their personality and loyalty depending on who is watching.
Used in a Sentence: She is a chameleon character who acts nice to you alone, but mean when popular kids are near. / Don’t trust a chameleon character who switches sides every single day.
Similar Expressions: Two-faced person / Social climber
19. Cheap talk
Definition: Insincere words of friendship that are not backed up by real loyalty.
Used in a Sentence: Saying you are my best friend while ignoring me in the hallway is just cheap talk. / I don’t care about your apologies because loyalty requires more than cheap talk.
Similar Expressions: Empty words / Insincere promises
20. Cloak of friendship
Definition: Using a fake appearance of warmth to hide unfriendly intentions.
Used in a Sentence: He wore a cloak of friendship just to borrow my notes and copy my homework. / Behind his cloak of friendship lay a jealous competitor.
Similar Expressions: False mask / Deceitful guise
21. Crocodile tears
Definition: Fake, insincere sadness or sympathy shown by someone who doesn’t actually care.
Used in a Sentence: She cried crocodile tears when caught spreading rumors, but she wasn’t truly sorry. / Don’t fall for his crocodile tears after he betrayed our group project.
Similar Expressions: Fake crying / Insincere sorrow
22. Cross double-cross
Definition: A complicated betrayal where a fake friend tricks you after pretending to help.
Used in a Sentence: Working with him on the fundraiser turned into a double-cross when he stole the credit. / I experienced a painful double-cross from someone I thought was loyal.
Similar Expressions: Treacherous trick / Ultimate betrayal
23. Cut you dead
Definition: When a fake friend suddenly pretends they don’t know you in public.
Used in a Sentence: After making new popular friends, she walked right past me and cut me dead. / It hurts when someone you helped suddenly cuts you dead at school.
Similar Expressions: Ignore completely / Give the cold shoulder
24. Fair-weather friend
Definition: Someone who is only your friend when things are good and leaves during hard times.
Used in a Sentence: When I broke my arm and missed soccer, my fair-weather friend stopped calling me. / You find out who truly cares when fair-weather friends disappear during a crisis.
Similar Expressions: Untrustworthy companion / Conditional friend
25. False coin
Definition: A deceitful person whose true untrustworthy nature is hidden underneath.
Used in a Sentence: My older cousin warned me that new classmate was a false coin. / Do not lend your favorite video games to a false coin who won’t return them.
Similar Expressions: Phony person / Deceiver
26. False praise
Definition: Insincere compliments given by someone who secretly envies or dislikes you.
Used in a Sentence: I could tell her compliments about my essay were just false praise. / Beware of false praise from people who never support you in private.
Similar Expressions: Flattery / Insincere compliments
27. Feed you a line
Definition: To tell you a false, smooth-sounding story to manipulate your trust.
Used in a Sentence: He tried to feed me a line about why he copied my homework without asking. / Don’t believe the excuses she feeds you because they are totally made up.
Similar Expressions: Lie to you / Feed falsehoods
28. Friendly enemy
Definition: Someone who smiles in your face while actively working against your success.
Used in a Sentence: Having a friendly enemy on the debate team made working together very stressful. / Watch out for that friendly enemy who smiles while sabotaging your notes.
Similar Expressions: Frenemy / Two-faced rival
29. Honeyed words
Definition: Sweet, flattering words spoken by a fake friend to hide malicious intent.
Used in a Sentence: He used honeyed words to trick me into doing his share of the chores. / Don’t let her honeyed words blind you to her dishonest actions.
Similar Expressions: Sweet talk / Flattering deceit
30. In name only
Definition: A relationship that exists officially or outwardly, but has no real care or loyalty.
Used in a Sentence: We were friends in name only after she started ignoring me at lunch. / Their partnership was a friendship in name only.
Similar Expressions: Nominal connection / Fake bond
31. Jackal in disguise
Definition: A treacherous, deceitful person who pretends to be harmless.
Used in a Sentence: The student who offered to help me study turned out to be a jackal in disguise when he stole my answers. / Beware of the jackal in disguise who offers fake comfort.
Similar Expressions: Deceitful person / Traitor
32. Judas kiss
Definition: A sign of affection or friendship that is actually used to betray someone.
Used in a Sentence: Welcoming me to the table with a smile before mocking my clothes felt like a Judas kiss. / His congratulatory pat on the back was nothing more than a Judas kiss.
Similar Expressions: Betrayal gesture / False affection
33. Keep your enemies closer
Definition: Watching a fake friend or rival carefully by staying close to them.
Used in a Sentence: I knew she talked behind my back, so I kept my friends close and my enemies closer. / In school politics, it pays to keep your enemies closer.
Similar Expressions: Monitor rivals / Watch closely
34. Knife in the back
Definition: A severe, sudden betrayal by someone you trusted as a companion.
Used in a Sentence: Sharing my private journal entries with the class was a total knife in the back. / Trusting him with my secret project idea resulted in a knife in the back.
Similar Expressions: Betrayal / Treachery
35. Leap of false faith
Definition: Trusting someone blindly despite signs that they are a fake friend.
Used in a Sentence: Lending him my rare comic book after he lied was a huge leap of false faith. / Don’t take a leap of false faith with someone who has broken promises before.
Similar Expressions: Blind trust / Foolish belief
36. Lip service
Definition: Saying you support someone with words while showing zero actual loyalty.
Used in a Sentence: He paid lip service to our friendship, but never helped when I needed a study partner. / Don’t settle for lip service when true friends offer real actions.
Similar Expressions: Insincere support / Empty words
37. Mask slips
Definition: When a fake friend accidentally reveals their mean or dishonest true personality.
Used in a Sentence: She smiled at the teacher, but when we walked into the hall, her mask slipped and she yelled. / You know someone’s true colors when their mask slips.
Similar Expressions: True nature shows / Facade drops
38. Mouse trap
Definition: A sneaky trick or trap set by a deceitful acquaintance.
Used in a Sentence: Inviting me to the party just to laugh at me was a cruel mouse trap. / I avoided the mouse trap he set by checking his rumors first.
Similar Expressions: Sneaky trap / Deceitful setup
39. Playing both sides
Definition: Being friendly with you while simultaneously gossiping with your rivals.
Used in a Sentence: You cannot trust someone who is playing both sides during a group argument. / She was caught playing both sides of the classroom rivalry.
Similar Expressions: Two-faced behavior / Switching sides
40. Poison the well
Definition: To ruin your reputation by spreading lies and turning others against you.
Used in a Sentence: He tried to poison the well by telling everyone false stories about my character. / Do not let a fake friend poison the well of your friendships.
Similar Expressions: Sabotage reputation / Turn people away
41. Put on an act
Definition: To pretend to be a loyal, caring friend when you actually do not care.
Used in a Sentence: Stop putting on an act of kindness when everyone knows you talk behind our backs. / He loves to put on an act for the teachers, but he is mean at recess.
Similar Expressions: Fake it / Pretend
42. Ride on coattails
Definition: A fake friend who uses your hard work and popularity to gain benefits for themselves.
Used in a Sentence: He did zero work on the science project yet tried to ride on my coattails for an A. / Stop trying to ride on my coattails and earn your own grades.
Similar Expressions: Use others / Parasitic friend
43. Salting the wound
Definition: Making a painful betrayal feel even worse by mocking you afterward.
Used in a Sentence: Mocking my low test score after you refused to share study notes was salting the wound. / Laughing at my mistake was like salting the wound.
Similar Expressions: Worsen pain / Mock suffering
44. Secret serpent
Definition: A hidden traitor who smiles at you while planning to hurt your feelings.
Used in a Sentence: The girl who borrowed my sweater and ruined it was a secret serpent. / Beware of the secret serpent in your club who pretends to be sweet.
Similar Expressions: Hidden traitor / Deceitful person
45. Shake with the right hand and stab with the left
Definition: Greeting someone warmly with friendship while secretly plotting against them.
Used in a Sentence: Shaking my hand while spreading rumors about my family is shaking with the right and stabbing with the left. / He acts like an ally, but he loves shaking with the right and stabbing with the left.
Similar Expressions: Two-faced betrayal / Treacherous act
46. Smiling assassin
Definition: A charming, friendly-looking person who ruins your reputation behind your back.
Used in a Sentence: She acts sweet during class elections, but she is a total smiling assassin with rumors. / Watch out for the smiling assassin who pretends to support your goals.
Similar Expressions: Charming traitor / Two-faced friend
47. Snake in the grass
Definition: A secret, treacherous enemy who pretends to be a loyal friend.
Used in a Sentence: I thought he was my buddy, but telling my secrets made him a snake in the grass. / Never trust a snake in the grass who smiles in your face and lies behind your back.
Similar Expressions: Traitor / Deceitful companion
48. Speak with a forked tongue
Definition: To lie, deceive, and say one thing to your face while meaning another.
Used in a Sentence: He speaks with a forked tongue when he promises to help us clean up and then leaves. / You cannot believe a word she says because she speaks with a forked tongue.
Similar Expressions: Lie / Be deceitful
49. Swallow the poison
Definition: To accept toxic, fake friendship because you are afraid of being lonely.
Used in a Sentence: Staying around kids who mock you is like choosing to swallow the poison. / Walk away from fake companions rather than swallowing the poison of their drama.
Similar Expressions: Tolerate toxicity / Accept fake bonds
50. Wolf in sheep’s clothing
Definition: A dangerous, untrustworthy person who disguises themselves as a gentle friend.
Used in a Sentence: The friendly new student who turned out to be a school bully was a wolf in sheep’s clothing. / Be careful who you share secrets with, as some people are wolves in sheep’s clothing.
Similar Expressions: Dangerous impostor / Deceitful enemy
Exercise to Practice
- She would act like a friend at school, but then spread rumors behind my back.
- He promised to back me up in the debate, and he actually helped me practice every single day.
- When I broke my arm and missed soccer, my fair-weather friend stayed by my side through everything.
- Stop putting on an act of kindness when everyone knows you talk behind our backs.
- He did zero work on the science project yet tried to ride on my coattails for an A.
- Sharing my private journal entries with the class was a total knife in the back.
- I thought he was my buddy, but telling my secrets made him a snake in the grass.
- She cried crocodile tears when caught spreading rumors, and she meant every single sob sincerely.
- You cannot trust someone who is playing both sides during a group argument.
- The student who offered to help me study turned out to be a jackal in disguise when he stole my answers.
- He used honeyed words to trick me into doing his share of the chores.
- True companions never break faith when entrusted with confidential thoughts.
- She is a chameleon character who acts nice to you alone, but mean when popular kids are near.
- Lying to everyone in your study group will completely burn your bridges.
- Saying you are my best friend while bringing me birthday cake and gifts is just cheap talk.
Answer Key
- True
- False
- False
- True
- True
- True
- True
- False
- True
- True
- True
- True
- True
- True
- False
Conclusion
Learning these idioms helps you recognize untrustworthy people and fake friends using descriptive language. Try using a few of these expressions when discussing character behavior in stories or movies to make your writing extra insightful.
Frequently Asked Questions
What are some common idioms for fake friends?
Common idioms for fake friends include phrases like snake in the grass, fair-weather friend, and wolf in sheep’s clothing. These expressions help describe deceitful people, backstabbers, and untrustworthy companions.
Why do we use idioms to describe fake friends?
Idioms give us vivid and memorable ways to express complex social dynamics and betrayal that plain words sometimes cannot capture. They make stories and conversations about relationships much more engaging.
How can I practice using these fake friend idioms?
You can practice by using these phrases when writing stories about characters learning who to trust or analyzing book characters. Matching them to everyday social situations is also a great learning method.
Are all fake friend idioms negative?
Yes, idioms describing fake friends focus on deceit, betrayal, and untrustworthiness, making them naturally negative terms used to warn others or describe difficult social experiences.
Can learning these idioms improve my social awareness?
Yes, knowing these figurative expressions helps you understand character motives in literature and recognize warning signs of insincere behavior in everyday interactions.
