Origin: Australian/American colloquialism.
Based on Happy Days character.... though evolving over the years...
Used for both Male or Female
Defined: Someone who thinks they are a bit too cool... Generally the person who dresses a bit over the top and/or always trying to "one-up" someone else’s comments, whilst tending to overdo everything they try to do....
In a Night-club where everyone is in cargo pants and shirts... “chachi” rocks up with the denim jacket and greased back hair, and sun glasses on his head at 2am...thinking he’s a little too good for everyone else at the club.
“Look at that guy over there....what a chachi....!”