abbrev. for Chill Out Slut; used when firing out the word "slut" is inappropriate, i.e. in a grocery store, courthouse, workplace, in front of children, etc. Encouragement for someone to relax, settle down, get out of your way, shut the hell up, etc.
Crazy bitch: "Did you hear about this and that and the other thing and this other thing and that person and what she did and he said and about what color underwear I'm wearing and what kind of weave do you have and where did you get that purse and did I tell you...."
Me: "OMG! COS! Seriously!
Me: "OMG! COS! Seriously!
by COSsayer April 16, 2011

"John really believes in COS, dude."
"Yeah he was wearing sweatpants and a sweatshirt to the club last night."
"Yeah he was wearing sweatpants and a sweatshirt to the club last night."
by COS pro June 07, 2013

by Raqueli88 September 05, 2006

John: Eric was really hammered last night after the fundraiser. He must have had 20 beers.
Jason: Yeah, he’s the COS.
Jason: Yeah, he’s the COS.
by Bamalama Johnson April 07, 2008

by Cake.Slaughter November 14, 2022

by Frank Rider August 23, 2009
