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.

Outwardly common looking item, that possesses something special or unique inside.

The exact opposite of a ricer. A Sleeper looks stock but is heavily modified to preform better. Sleepers are often, like ricers, economy cars. Unlike ricers, sleepers can also be regualr sedans or any other vehicle that was not meant to be a preformance vehicle. Sleeper cars are ussually modified with boost (super or turbochargers), transmisions, and sometimes full engine swaps. Many people who drive sleepers use them to hustle at the strip or avoid attention from the cops. Many auto makers offer factory sleepers that are a sport version of the origional economy sedan with very few external changes. Some of the best sleepers of all time came from the muscle car era. The 1972 Chevy Nova is considered one of the best sleepers. The Nova is one of the most popular models to get turned into a sleeper. Most sleepers aren't true sleepers because they will have aftermarker gauges visible (real sleepers hide them in the glove box), racing slicks and loud pipes. A true sleeper will not be exposed until they reach the end of the track.

Large, beautiful breasts that are keep well consealed and initially appear to be much smaller and less impressive than they actually are until unleashed.

A car that looks stock on the outside but is putting out some serious power under the hood.

a person who is an outwardly common looking item, but possesses something special or unique inside

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.