A mashed up word for "ok", "thanks", and "goodbye". It is commonly used on quicky text messages.
Please buy me a soda when you go to the convenient store. Kthxbai!
by callbooks December 18, 2009
Okay, thanks, goodbye for people you really don't like. Used as a derogatory term for idiots.
IOWNULOLZ: hay cn u giv me fre stuf ur rich
Me: No. Go die in a hole, kthxbai
by Ultib June 28, 2007
Okay thanks bye in leet.
Dude 1: i'm liek gona go now. kthxbai.
Me: Bye fool.
by DoomBringer316 February 11, 2004
derrives from the phrase "kthxbye"
by kevin February 5, 2003
The internet way of saying "Okay, thanks, bye".

It is mostly used in contempt or just a humorous way to bid someone goodbye.
"Yeah well I'm gonna go to sleep now, kthxbai"
by Hi I'm Awsum July 16, 2015
1. A abbreviation of “k thanks bye
2. A motherfucker who, in September 2019, hacked the oldest YouTube video and made it a living dump of like and sub beggars.
1. “Here are your clothes” “kthxbai
2. “Man that kthxbai hacker is a bitch”
by Skullman842 April 27, 2020