Referring to a car, it is a car whose cosmetics look like it's stock and slow and one assumes there is a small engine under the hood. Only when it is challenged by a ricer or another car, it shows its mighty by leaving the other car in a cloud of smoke because it has either a huge engine from the factory or has a swapped engine from a bigger car or has tons of engine modifications.

A sleeper is is the perfect example of this acronym "All bite, no bark."

A person who enjoys sleeping and sleeps all the time.

I am a sleeper

A radical, who hides his or her beliefs in order to prevent suspicion from any authority figure; an extreme liberal who pretends to be a conservative, usually for gaining money to fund a revolution.

When you know and feel you will have to take a huge and possiblly painful shit later in the day.

To have sexual relations with another while they remain asleep.

one who sleeps

To start having sex with somebody while they're asleep.