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!
Frank Sheeran: "Tony told the old man to tell me to tell you... 'it's what it is'"
Jimmy: "What it is?"
Frank: "It's what it is."
Jimmy: *sniffling* "They wouldn't dare"
or
Tim: "The pharmacy won't process my refill. I tried everything."
Nick: "Not even for tomorrow?"
Tim: "It is what it is. I'm out of ideas."
Nickname given to bales of marijuana thrown overboard or out of airplanes. Origin is reportedly from members of the USCoast Guard in the area of Southern Florida.
"Base we've got some square groupers floating outside of Miami harbor."
A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.
I had a trucker's tan after driving for 10 straight hours on a sunny day.