D defs.my
Entry 2 senses Webster, 1913

bummer

/(bŭm"ẽr)/ · bum·mer · IPA /ˈbʌ.mɚ/
01 n. An idle, worthless fellow, who is without any visible means of support; a loafer; a dissipated sponger; one who bums.
  1. 1.
    An idle, worthless fellow, who is without any visible means of support; a loafer; a dissipated sponger; one who bums.[Slang, U.S.]
  2. 2.
    an unpleasant event, experience, or situation; as, getting caught in a cloudburst while wearing my best suit was a bummer.[Slang, U.S.]