An all but lost phrase from the seventies era of ebonics, the closest contemporary equivalent being, "What up?" WHAT IT IS is often a rhetorical question like, "How's it hanging?" or "What's going on?"

The never fail perfect deflector. Always a perfect and easy escape route away from sticky situations. When asked "What?", you reply with the same response, and no one can ever really come up with a response to it.

A final solution to a situation, usually after much deliberation, and a final acceptance of that fact. It can be giving up on expecting someone to show up, or as it's typically used amongst The Mafia, a death sentence.

The simplest definition is: a ultimate, final acceptance. Period. Past all points or avenues of trying to change the situation. Gun at your head, you're done crying, he's not hearing you out. It is what it is. Get on with it motherfucker!

One of the only 3 words that Lil Jon says, the other two being "YEAH!" and "OKAY!"

Simply stated means, "There is nothing that you may do about it. So, you must just accept it"

used to ask someone what they said or what was meant by a certain gesture

A phrase with wrong grammar, but it is already widely accepted in the English Language, as it is also widely used in public. The 'what that is' phrase could be used at the end of a question, e.g. Do you know what that is?, but now it could also be used as a single question: What that is?