n. 1. An idle, worthless fellow, who is without any visible means of support; a loafer; a dissipated sponger; one who bums. [ Slang, U.S. ] [ 1913 Webster ]
2. an unpleasant event, experience, or situation; as, getting caught in a cloudburst while wearing my best suit was a bummer. [ Slang, U.S. ] [ PJC ]