know what’s what
know what's what
To know the true facts or most fundamental information (about someone or something). Kid, I've been doing this job for longer than you've been alive, so trust me when I say that I know what's what around here.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
know what’s what
tv. to be aware of what is going on in the world. We don’t know what’s what around here yet.
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.