Source : Webster's Revised Unabridged Dictionary (1913)

Swimmer \Swim"mer\, n.
   1. One who swims.

   2. (Far.) A protuberance on the leg of a horse.

   3. (Zo["o]l.) A swimming bird; one of the natatores.

   {Little swimmer} (Zo["o]l.), a phalarope.

Source : WordNet®

swimmer
     n 1: a trained athlete who participates in swimming meets; "he
          was an Olympic swimmer"
     2: a person who travels through the water by swimming; "he is
        not a good swimmer" [syn: {natator}, {bather}]