(idiomatic, US) As an interrogatory, indicative of a nonchalant attitude towards potential criticism, not caring about what other people think, confident and self-possessed.

(idiomatic, humorous) Used to express surprise about someone's uncharacteristic or wacky, offbeat past actions.

Alternative form of what's your job

Inquires about the subject's current occupation.

Used to ask what the interlocutor is currently doing.

(US, colloquial, often preceded by hey) Used to express surprise or dissatisfaction with an action or statement of another person, especially to that person.

Events that have already taken place cannot be changed and actions that have already been committed cannot be undone, so it is best not to dwell on them.

(rhetorical question, somewhat hostile) Expresses discomfort because the interlocutor is looking at something; usually, this is said when the interlocutor has been staring at the speaker.

Alternative form of what's-his-name

(MLE, MTE, slang) what's up, what's happening (a greeting)