bounc·er I. \ˈbau̇n(t)sə(r)\noun (-s) 1.Britain a.: boaster, bully, liar b.: lie, whopper 2.: something big : a good stout example of the kind < that baby is a bouncer > 3.: one that ejects disorderly persons (as at a dance hall, gambling house, or barroom) or keeps gate-crashers out (as at a party or ceremony) 4.slang: caboose II. noun 1.: bumper IV,1f 2.: a batted baseball that bounces