English slang: what common slang words mean
Short answer: Slang is very informal language that friends use in chat, songs and videos, such as “lit” (very exciting) or “no cap” (I am not lying). It changes fast, so a word can change meaning or go out of date. Use it with friends and online, not at school, at work or in formal writing. This guide explains 25 common slang words and how informal each one is.
At a glance
| Slang | Meaning | Example |
|---|---|---|
| Lit | very exciting or fun | That game last night was lit. |
| No cap | I am not lying | That was the hardest quiz of the year, no cap. |
| Sus | seems strange or not honest | Why is he hiding his phone? That's sus. |
| Ghosted | stopped answering someone without saying why | I sent three messages, but she ghosted me. |
| FOMO | worry about missing the fun | I stayed up late because of FOMO. |
| Low-key | a little, without showing it | I'm low-key tired of this song. |
What is slang?
Slang is a set of words and phrases that a group of people use with each other, usually in casual talk and online. A slang word can be a new word, such as “sus”, or an old word with a new meaning, such as “cap” (a lie). You learn slang to understand what you hear, even if you never say it yourself.
Is slang safe to use?
- Slang is very informal. It is fine with friends, in casual chat and in comments online.
- Do not use it at school, at work, in a message to someone you do not know, or in any formal text.
- Slang changes fast. A word can go out of style in a year or two, and its meaning can change. Check how people use a word now before you use it yourself.
- Some slang sounds rude or confusing to people who do not know it. When you are not sure, use a plain word instead.
Six words that need extra care
These six words are very informal, so the Teen Talk lessons mark them with a label. Understand them when you hear them, and think before you use them.
| Slang | Meaning | Why take care |
|---|---|---|
| Bae | someone you love or are dating | It is a very personal word. Use it only with someone you are close to. |
| Ghosted | stopped answering someone's messages without saying why | It describes something that can hurt. Do not use it as a joke about a person. |
| YOLO | you only live once; said to support a bold choice | It is often used to encourage risky choices, so it can sound careless. |
| No cap | I am not lying | It is very casual and can confuse people who do not know it. |
| Sus | seems strange or not honest | Calling a person “sus” can sound like an accusation. |
| Cap | a lie; something not true | Saying “that's cap” tells someone they are lying, which can sound rude. |
Common mistakes with slang
- Using slang in a formal place, such as an essay or a job email.
- Using it too often. A few well-chosen words sound natural; many sound forced.
- Copying a meaning from one video without checking. The same word can mean different things in different groups.
- Mixing up similar words. “Cap” is a lie, but “no cap” means “I am not lying”.
Slang about friends and feelings
These words are about the people close to you and about how you feel when plans change.
| Expression | Meaning | How informal |
|---|---|---|
| Fam | Your family or very close friends | Informal |
| Bae | Someone you love or are dating | Very informal |
| Ghosted | Stopped answering someone's messages without saying why | Very informal |
| FOMO | Worry that friends are having fun without you | Informal |
| Bail | To leave or cancel plans | Informal |
Slang about friends and feelings: what the words mean
Slang for saying something is great
These are the words people use to say that a song, a game, a trick or a person is very good.
| Expression | Meaning | How informal |
|---|---|---|
| Lit | Very exciting or fun | Informal |
| Dope | Very cool or good | Informal |
| Fire | Very good or exciting | Informal |
| Sick (as praise) | Very cool or impressive | Informal |
| Legit | Real, or very good | Informal |
| Slay | To do something very well | Informal |
| Go off | To perform very well or speak strongly | Informal |
| Score | To get something you really wanted | Informal |
Slang for saying something is great: lit, dope, fire, slay
Slang about honesty
These three are about telling the truth, telling a lie and not trusting something.
| Expression | Meaning | How informal |
|---|---|---|
| No cap | I am not lying | Very informal |
| Cap | A lie; something not true | Very informal |
| Sus | Seems strange or not honest | Very informal |
Slang about honesty: no cap, cap and sus
Slang about attitude and plans
These words show how sure you are, whether you agree, and how you want to live.
| Expression | Meaning | How informal |
|---|---|---|
| Low-key | A little, or without making it obvious | Informal |
| High-key | Very much, or without hiding it | Informal |
| Bet | Okay; I agree | Informal |
| I'm down | I agree. I want to do it | Informal |
| YOLO | You only live once; said to support a bold choice | Very informal |
| Main character energy | Acting very confident, like the star of a story | Informal |
| It's giving... | It looks or feels like something | Informal |
| Rent-free | Something you keep thinking about | Informal |
| Loaded | Having a lot of money | Informal |
Slang about attitude and plans: low-key, bet, YOLO and more
Slang or idioms?
Slang is very informal and changes fast. Idioms are fixed phrases that stay in use for a long time. If you want to learn expressions that are safe in most situations, read the English idioms guide. For formal texts such as essays, see the English writing guide.
Questions
What is slang?
Slang is very informal language that a group of people use with each other, mostly in casual talk and online. It changes fast and is not for school, work or formal writing.
What does “no cap” mean?
It means “I am not lying” or “I really mean it”. People say it after a strong opinion: “This is the best song of the year, no cap.” It is very informal.
What does “sus” mean?
It means something seems strange or not honest. It comes from the word “suspicious”. It is very informal, and calling a person “sus” can sound like an accusation.
Is slang safe to use at school or work?
Usually not. Slang is very informal, so it is better with friends and online. At school and at work, use plain words. Learn slang so you can understand it when you hear it.
Will slang go out of date?
Some of it will. Slang changes fast, and a word can lose its meaning or sound old in a short time. That is why it is useful to learn what a word means now, and to check how people use it.
What is the difference between slang and an idiom?
An idiom is a fixed phrase with a special meaning that people use for a long time, such as “a piece of cake”. Slang is very informal and changes fast, such as “lit”. Many idioms are fine in daily speech, but slang is only for casual talk.
How can I practice slang on English for Fun?
The Teen Talk tool in the Learning Path has 25 short lessons. In each lesson you hear the slang word, learn its meaning in English, use it in a sentence, choose the right situation and say it yourself. Very informal words carry a label. The first lesson, “Lit”, is free to try; the rest is part of Full Access.
Part of the 🗣️ Teen Talk tool. Đọc bằng tiếng Việt.
Written for English learners by the English for Fun team. How we write our lessons · Last updated 2026-11-05.