Verb: know what's what
- Be well-informed
"He knows what's what when it comes to office politics";
- know the score [informal], be with it [informal], be on the ball [informal], know what's going on
- Be experienced and familiar with how things work
"After a month on the job, she really knew what's what";
- know the ropes
Derived forms: knowing what's what, knew what's what, knows what's what, known what's what
Type of: know