bouncer

1. A person or thing that bounces something, such as a ball.
2. A member of security personnel employed by bars, nightclubs, etc. to decide who can enter, maintain order, and deal with patrons who cause trouble. (informal)
3. A short-pitched ball that bounces up towards, or above the height of the batsman’s head.
4. An account or server (as with IRC and FTP) that invisibly redirects requests to another, used for anonymity or vanity.
5. One who bounces; a large, heavy person who makes much noise in moving. (dated)
6. Something big; a good stout example of the kind.
7. A bouncy castle.
8. A kind of seat mounted in a framework in which a baby can bounce up and down.

Plural bouncers