Someone who has no idea that they aren't cool. Often affiliated with "Hipster", a chillster is actually a step below. All previous definitions for chillster are wrong, seriously.. think about it. Do you really want to be a chillster?
ex 1."Are you Listening to Avenged Sevenfold on terrible subs in your beat up Intrepid? Dude you are such a chillster"
"Haha- LOL I know bro, chillin forsure"
ex 2 "haha bro we are such buds, but I snitched on you to the cops for money."
"Okay you chillster"