Cap: meaning, examples and when to use it
Short answer: “Cap” means a lie, or something that is not true. People say “That's cap” to tell someone that they do not believe them.
What does “Cap” mean in English?
In slang, “cap” is a lie. If you say “That's cap”, you say that something is false. The word is not about a hat. It is almost always used about a statement that you do not believe.
Examples of “Cap”
- He said he can fly a plane? That's cap.
You do not believe the story. - No way she ran a marathon. That's cap.
You think it is not true. - Everyone says the test is easy, but that's cap.
You think the claim is false.
When do you use “Cap”?
- When you think that something is not true.
- In casual chat with friends and online.
- As a short comment: “Cap.”
Is “Cap” safe to use?
The Teen Talk lessons mark “cap” as very informal. Saying “that's cap” tells a person that they are lying, so it can sound rude. At school, at work and in formal writing, say “I do not think that is true”. Slang changes fast, so its meaning can change.
Common mistakes with “Cap”
- Do not mix it up with “no cap”. “No cap” means “no lie”.
- It is not about a hat.
- Do not say it to someone you do not know well.
Similar expressions
- The opposite is “no cap”. A related word is “sus”. Group: slang about honesty.
Questions
What does “Cap” mean in English?
“Cap” means a lie, or something that is not true. People say “That's cap” to tell someone that they do not believe them.
Is “Cap” safe to use?
The Teen Talk lessons mark “cap” as very informal. Saying “that's cap” tells a person that they are lying, so it can sound rude. At school, at work and in formal writing, say “I do not think that is true”. Slang changes fast, so its meaning can change.
What does “that's cap” mean?
It means “that is not true” or “you are lying”.
Is “cap” rude?
It can be, because it says that someone is lying. Use it only with close friends.
Part of the English slang guide and of slang about honesty, in the 🗣️ Teen Talk tool.
Written for English learners by the English for Fun team. How we write our lessons · Last updated 2026-11-05.