False Crack 

A Hawaiian slang term meaning a punch to the face and, from what I thought, often done without much more than a verbal warning at most. A surprise punch that catches the recipient at least somewhat off-guard.

Also just to "false" or getting "falsed"
Also "dirty cracks" or "dirty lickings"

Dey wuz arguing for so long until James jus wen false crack em!!!

He was talking shit so I falsed dat faka and he wen drop li' dat!!!

False Crack by JLiRD March 5, 2007

false crack 

A hard punch to the face. Used colloquially in Hawaii as part of the local dialect of pidgin English.

You betta watch yo' mout or you gonna get one false crack, bra.

It would be highly advisable if you were to choose your words with care, or else you will receive one false crack, sir.

false crack by blastron May 13, 2005

falsecrack 

to blindside, or cheap shot someone.

He came out of nowhere and falsecracked me upside the head

falsecrack by McDoodle The Third May 18, 2008