Contraction of what is more.

(euphemistic) what the hell

(mildly vulgar, slang) An intensive form of what. / (mildly vulgar, slang) Indicating acceptance, indulgence, or insouciance: Why not? Who cares?

(slang) Used other than figuratively or idiomatically: see that's, what's up. / (slang) Used to express acquiescence or concurrence; true; indeed.

(colloquial, rhetorical question, impolite) A reply to an unimportant or irrelevant statement, indicating indifference on the part of the speaker.

(Ireland) What's happening?

(slang) what is happening?; what's up?

(euphemistic) what the hell

Alternative form of what's the craic

(colloquial) What do you want to drink?