A term used to describe the act of grabbing a female's breast with ones hand, twisting it, and pulling on it before releasing. This is best done while yelling "doorknob" in their face.
The term doorknob was coined by a Canadian who likened this act to that of opening a door.
"Chris' girlfriend was being a bitch so he doorknob'd her at the party in front of everyone, he's now single."
"If a girl kicks you in the junk you should retaliate with a doorknob."
A word shouted when an elder has been angered. Causing them to throw a doorknob at one's head. Also a replacment for "head's up" "look out" or "duck"
Class of noisy kids: *blah blah blah boys and ponies and hair and myspace.com blah blah*
Angered teacher:*throws doorknob*
student:DOORKNOB!!
*everyone ducks*