Source : Webster's Revised Unabridged Dictionary (1913)

Bloomer \Bloom"er\, n. [From Mrs. Bloomer, an American, who
   sought to introduce this style of dress.]
   1. A costume for women, consisting of a short dress, with
      loose trousers gathered round ankles, and (commonly) a
      broad-brimmed hat.

   2. A woman who wears a Bloomer costume.

Source : WordNet®

bloomer
     n 1: a flower that blooms in a particular way; "a night bloomer"
     2: an embarrassing mistake [syn: {blunder}, {blooper}, {bungle},
         {foul-up}, {fuckup}, {flub}, {botch}, {boner}, {boo-boo}]