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to go to sleep (to "knock out")
n00b: okies, itz gettin l8, im gunna KO ^_^ 99!!!!!11
by swishersweets April 09, 2008
"KO" is the equivalent to the meaning & abbreviation of the letters meaning "OK" and was used on "Mork & Mindy", which is a t.v. series that had aired from 1978 to 1982. Mork is one of the main characters in the series, and an alien from the planet Ork. He would commonly reverse the proper order of human words and phrases that he spoke, by mistake
"Owie! Shazbot, shazbot, SHAZBOT! I stubbed my little toe when I tripped over the footstool Mindy, and it hurt!!! You didn't even ask me if I was KO!!!"

(Mindy replies)
"Oh, Mork! I'm sorry- did it hurt? I think you meant to say that I didn't ask you if you were "OK", on Earth we ask if you are OK if you hurt yourself, not "KO"!!!

***Proper credit must be given to the true comic genius of Robin McLaurin Williams (July 21, 1951 – August 11, 2014) R.I.P.
by green eyed lady 13 August 18, 2014
1. When you knock someone out.

2. When u're knocked out
1. The K-O (knock-out) of Badr Hari was wonderfull!

2. Im totally K-O
by desibabe July 04, 2009
Knifed-Out; taken down by a melee weapon in (any game).
The leet player was ko by a noob.
by l337no0bi3 February 12, 2009
1. ko is a person who has a fro
2. Ko is a person who is a pro in J walking
3. Ko is a Gigolo which you call a man ho
4. Ko is an Aviator
5. Ko could also meen a short fat person.
Ko can u brush your fro with a fro pick?
Ko how many girls can you fuck in a day?
Look at that Ko.
by Ariel Gad January 25, 2007
KO! means bloodrider in serbian , someone like bro to you.
You help each other, and together torture some jagnjetji people...or maybe kill them..or rape them...whatever.
KO!'s are fearless warriors and make lots of funny jokes 'bout jesuss , skins , grand parada , rastko pornitjar , skins , steven segaul , blackers and bora.
-Desi bre KO!Oces da ubijes slavicu?
-Desi KO! lets kill some jagnjetji people!
-KO! \/ E |- .!.
by krvorodnik October 05, 2006
OK backwards. Originally from Short Circuit 2 (1988), K.O. Derf is OK Fred backwards. Became more common with the rise of chatrooms and IM with people who can't or don't waste time trying to type well.
fred: are you ok?
#5: Functioning 100%. Perfectly K.O., Derf!
fred: it's fred
#5: That's what i said, Derf!

im user 1: i gtg
im user 2: wait bring that cd tomorrow
im user 1: ko durf ttyl
by joefitz July 19, 2005