look up any word, like half chub:
 
1.
-to calm down
-relax
-used synonymous with "chill out"

term was used regularly in the 1970s. rarely used presently
yo,my man, cool out son!
by sye June 09, 2005
 
2.
to chill the fvck out
i know you're pissed but you need to cool out.
by justine December 03, 2003