sleeper 

Bowling term for a pin which is directly behind or in front of another pin.

Also a wrestling hold to make your opponent pass out.

Shut up or I will put you in the sleeper hold.

sleeper by maybenot September 5, 2003

Sleeper 

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."

It is a sleeper dude, that is what it meant to do, shock you by its speed and power you never thought it had.

Sleeper by Sleepers are the S*** July 15, 2011

Sleeper 

A person who enjoys sleeping and sleeps all the time.

I am a sleeper

I’m a sleeper

Sleeper by Tegand1312 April 9, 2019

sleeper 

Something that is boring or not fun

That party was so sleeper

sleeper by AnonymousChickenCollector January 21, 2021

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.

James Cole believed a schizophrenic person was going to release the virus; it turned out a sleeper did the job.

sleeper by Vash Westland August 24, 2003

sleeper 

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

"Dude, this sucks man, I've got a sleeper."

sleeper by Cascone September 25, 2008

sleeper 

one who sleeps

hey look! that sleeper's sleeping.

sleeper by yellow fever October 13, 2003