Common American slang and phrases, explained

“What’s up,” “I’m down,” “no worries” and 30 other everyday phrases, with what they actually mean.

By USA Life Nest Editorial Team
Last reviewed Jul 29, 2026 · 3 min read

You can speak excellent English and still get lost in a casual American conversation. Most confusion comes from a small set of everyday phrases.

Greetings

Phrase	Meaning
What’s up? / Sup?	Hi, how are you? Reply: “Not much, you?”
How’s it going?	Hi. Reply: “Good, thanks.”
Hey there	Friendly hello
Take care / Have a good one	Goodbye

Phrase	Meaning
I’m down	I want to join
Sounds good	Okay, agreed
I’m good	No thanks (when offered something)
Rain check	Let’s do it another time
No worries	It’s fine / you’re welcome

Tip: If you don’t understand, it’s fine to ask: “Sorry, what does that mean?” People usually enjoy explaining.

What does “I’m good” mean?

Usually “no thank you” when someone offers something, or “I’m fine” as a greeting reply.

What does “rain check” mean?

A polite way to postpone plans.

Is slang okay at work?

Light, common phrases are fine; avoid very casual slang in emails.

USA Life Nest Editorial Team

Written and reviewed by people who moved to the US as students, workers and families. We update guides when rules or prices change.