noun

• (informal) A member of security personnel employed by bars, nightclubs, etc. to decide who can enter, maintain order, and deal with patrons who cause trouble.
  "At 199 centimetres and a hundred kilos going up, he was scary big and he found work as a bouncer and enforcer[.]"
• (cricket) A short-pitched ball that bounces up towards, or above the height of the batsman’s head.
  "‘You try to hit the bouncer that you should duck under. Your bat misses it completely. The ball strikes your temple, whack!’"
• (Internet) An account or server (as with IRC and FTP) that invisibly redirects requests to another, used for anonymity or vanity.
• (dated) One who bounces; a large, heavy person who makes much noise in moving.
  ""Why, I'll tell you, Mr. Simple; he's a good tempered, kind fellow enough, but—" / "But what?" / "Such a bouncer!!" / "How do you mean? He's not a very stout man." / "Bless you, Mr. Simple, why don't you understand English. I mean that he's the greatest liar that ever walked a deck.[…]""