Often reffering to what appears to be a ordinary looking stock commuter car that is anything but stock under the hood. Pretty much the exact opposite of your every day riced up civic.
My bone stock looking 1967 Volkswagen Beetle with a dual carbed, big bore and race head equiped engine gives quite the ego bashing when a ricer can't hold up to his own challenge at a light.
by VWtuner June 6, 2003
someone who secretly is badass at something but doesnt let anyone know
guy 1: im literally boutta destroy him at insert game/activity
guy2: oh no man dont do that hes a sleeper at that game/activity
by JavaLime May 1, 2020
Outwardly common looking item, that possesses something special or unique inside.
That boring looking car is a real sleeper with that big turbo hiding under the hood and nary a sticker or scoop to be seen anywhere on it.
by sageoneon March 7, 2003
A car that looks stock on the outside but is putting out some serious power under the hood.
"Damn, your car is freaking fast! You planning on putting a bodykit or drag spoiler on it?"

"Nah, I prefer the sleeper look."
by dragonfly12345 February 7, 2006
a person who is an outwardly common looking item, but possesses something special or unique inside
Cyndi turned out to be a sleeper, I thought she was just a bar fly but she has an M.A.Sc. in Electrical Engineering and owns half a restaurant with her youngest uncle.
by Jake March 25, 2004
someone who has the potential to get hot so later someone can smash
hey, you see that kid Kyle over there he must be a sleeper
by Justinbrooks99 December 19, 2017
A chick that you don't think is hot at first, but after a period of time, you come to the conclusion that this girl is very hott.
Yea, this girl is a sleeper. I didn't think she was hot at first, but after a brief period of time, I came to the conclusion that she is very hott.
by Ryaun December 10, 2006