what's with somebody?

What's (up) with (someone)?

Why is someone so upset or acting in such an unusual way? What's with Jeff? He just screamed at me and stormed out of the room. I wonder what's up with Sarah—she's been avoiding me for days now.

what’s with somebody?

(American English, spoken) used to ask why somebody is behaving in a strange way: What’s with you? You haven’t said a single word all morning.