Sarcastically used to point out an unfunny joke. It originates from the act of slapping one's knee during vigorous laughter. Later took on a sarcastic meaning.
Comedian: I just flew in from Los Angeles, and boy are my arms tired!
Audience member in sarcastic tone: wow that's a real knee-slapper
Audience member in sarcastic tone: wow that's a real knee-slapper
by Joe February 11, 2003
Get the knee slappermug. by Joe May 13, 2005
Get the bathcummug. by Joe May 01, 2005
Get the sperm whoremug. 
1. A rigatory exclamation used in paranormal scenarios. 2. A proclamation of happiness and/or confusion. 3. The outer lining of a male rectum.
by Joe July 16, 2004
Get the Gangs Parsarvusmug. I can't believe all of the things people have written here. Long Island can't be upstate solely based on that fact that is the southern-most part of New York. With that said, Most areas such as Nassau County and Western Suffolk County are not rural. Rural areas are hours from any type of city, having farms and acres of unused land. None of that is in any of these areas. I think that you people are just being defensive about where you are from. Nassau County is not an hour from the city. With traffic permitting, it is slightly over a 1/2 hour from the eastern part. I wont compare LI to Manhatten because Manhatten is Urban, but areas in queens are just as nice, and much nicer than areas on Long Island. We do have nice areas, but we also have bad areas as well. Areas like Hempstead are just the same as some parts of Queens, accept it.
stop being ignorant and labeling people from Long Island as "hicks," especially being that there are places in Nassau County that are under a mile outside of Queens.
by Joe May 13, 2005
Get the long islandmug. Indentured, underage, over-inibriated, completely lacking in common sense and personal hygiene, servants of the slumlord of south arkansas known as Tony Avo
by Joe May 27, 2003
Get the los avo'smug.