An unattractive person used for one time only non-comittal sexual relationships...
Steve pulled his friend Larry aside at the bar, pointing excitedly for Larry to look. "Hey brah see that real dog on the other side of the bar with that pimply face and that junky butt? Why don't you be a gentleman and knick knack paddy whack give a dog a bone?"
by Lincolnfx1423 November 23, 2009
Spontaneously jizz in your pants
After having not masturbated in two days, I knick knacked in my pants during geography class.
by Brownbottom Cupcake May 04, 2009
the thing you wear under your pants/skirt, not to be confused with "panties" which is a retarded american word that we have no use for. See also: underwear
Gotta get some new knick knacks, my old ones have mysteriously disappeared
by Immi_callmepnk August 25, 2007
Hey, I'm gunna have a knick knack before the movie, want one?
by bird January 02, 2004