To be beaten to death by a large black rubber dildo.
In the movie Lock Stock and
Two smoking barrels, the character Hatchet Harry, beats a man, suspected of stealing, to
death with what happened to be at hand. Harry, also a porn shop owner, happened to grab a big black rubber cock.
This term arose due to the unwieldlyness of the lengthy phrase "He was beaten to
death with a large black rubber cock..." and was shortened to simply, "He got gonked."
Hatchet Harry gonked some
bloke for
stealing from him.
If these guys keep pissing
us off like this, I'm gonna gonk them.