what's up

colloquial idiomatic in the sense of "of concern" with-up US in the sense of "happening" rhetoric

Japanese Meaning

どうしたの？ / 何か問題でもあるの？ / どうかしたの？

You seem really upset today—what's up?

今日は本当に気分が落ち込んでいるように見えるけど、どうしたの？

Sense（1）

You're looking a bit miserable. What's up?

Sense（2）

(idiomatic, colloquial, chiefly US, with up in the sense of "happening") What's happening? What are you doing?

Hey, what's up? – Not much, just working.

Sense（3）

(rhetorical question, colloquial) A casual greeting with a meaning similar to how are you? or nice to meet you.

Hey, what's up? – Hey! Good to see you.