Source : Webster's Revised Unabridged Dictionary (1913)

Sweater \Sweat"er\, n.
   1. One who sweats.

   2. One who, or that which, causes to sweat; as:
      (a) A sudorific.
      (b) A woolen jacket or jersey worn by athletes.
      (c) An employer who oppresses his workmen by paying low
          wages. [Slang]

Source : WordNet®

sweater
     n 1: a crocheted or knitted garment covering the upper part of
          the body
     2: a person who perspires [syn: {perspirer}]