look up any word, like doxx:
 
4.
To do something with the best of your ability; to become a legend in the process or to achieve 1337 status whilst performing the said phrase.
B: Hey YO JOE!! What did you wind up doing last night ?

Joe: YO SON, I WAS KILLIN IT!

B: OHHH SHNAP! THATS WHATS UP MY NINJA!
by FPSTOM January 19, 2010
 
1.
1.to be doing something very good

"john was killin it all day long in the competition"

2. to do your own thing, in a sorta funny way
1. "john was killin it all day long in the competition"

2. "max is killin it in his overalls"
by alex July 16, 2004
 
2.
To have sex in a hardcore manner.
I walked in on Johny killin it with Kortnee.
by Mr.Business April 27, 2004
 
3.
did it very well, you were the best at it,did something extremly good
when I dance I be killin It, I was killin it when I was singin that song
you killed it homie
by Nikki Banks April 25, 2009
 
5.
Someone who is doing very well in every facet of life
Why is the wolf killin it so much
by BRICKO November 18, 2010
 
6.
A way of saying someone is really good at dancing or other active motions
Ay yo brah u is killin' it from party rock anthem.
by xXPowaXx September 05, 2011
 
7.
Masterbation; Whacking off; touching one's self
"I walked in on Keefer Killinit yesterday."

Also used:
Ben was killin' his dick yesterday.
by Killit King February 05, 2010