what's what


Also found in: Dictionary.

what's what

(spoken)
the information about a person or situation You finally met her boyfriend, so now you know what's what. He's been in this business for a long time and really understands what's what. It will be hard for investors to tell what's what in the current stock-market crisis.

what's what

Informal
The fundamentals and details of a situation or process; the true state or condition.