by SALKFJsalfk February 17, 2008

by Erak22 September 27, 2009

A blunt that is so large, or otherwise so potent, a hit causes you to slap your knee and say "GAH'DAM."
by The Pizza Man April 20, 2006

by JarMa13 December 3, 2018

Guy 1: what do you call cheese that isn't yours?
Guy 2: Idk what?
Guy 1: nacho cheese
Guy 2: now that's a knee-slapper!!!
Guy 2: Idk what?
Guy 1: nacho cheese
Guy 2: now that's a knee-slapper!!!
by billystiggle February 3, 2012

something really funny (from the slapping of the knees and hitting the floor associated with laughter.
by The Return of Light Joker September 27, 2008

1) An otherwise unfunny, awkward, or just stupid joke. Usually a dad pun or something of the sort. Said after this to show that it should have never been said in the first place. Invented by hillbillies and rednecks when sitting on their porches, slapping their knees when somthing funny happens.
2)said after something funny and stupid happens.
2)said after something funny and stupid happens.
1)
dumb guy:"Two peanuts are walking down the street, and one of them was assaulted!"
normal guy (slaps knee and fake-laughs):"Wow! That sure was a knee slapper!"
2)
guy skates and falls off rail, hurting his knee and friend laughs.
Later they are talking and laughing about a dumb joke.
friend:"wow that sure was a knee slapper!" (slaps knee)
skating
guy:"yea!"(slaps knee very hard, and dislocates it from the earlier accident)
friend:"no that's a knee slapper!"
dumb guy:"Two peanuts are walking down the street, and one of them was assaulted!"
normal guy (slaps knee and fake-laughs):"Wow! That sure was a knee slapper!"
2)
guy skates and falls off rail, hurting his knee and friend laughs.
Later they are talking and laughing about a dumb joke.
friend:"wow that sure was a knee slapper!" (slaps knee)
skating
guy:"yea!"(slaps knee very hard, and dislocates it from the earlier accident)
friend:"no that's a knee slapper!"
by dhawk123 March 8, 2009
