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 LondonBridgeisFuckingDown
A piece of jewelry. A trinket or bauble.
Look at the knick knack that girl is wearing around her neck.
By Plummkin
a cigarette
Hey, I'm gunna have a knick knack before the movie, want one?
By bird
Jack ass, typically said to someone that is worth less than a tourist trap item
Did you see quintin harassing that girl, yeah hes a real Knick Knack
By Theknackattack
Used as one of many ways of saying nigga without actually saying nigga. Commonly used by corny white folks who don't know any better.
white friend: yo what up my knick knack black friend: goofy ass
By pushinp