A Sweater

1. A knitted jacket or jersey, usually of thick wool, worn by athletes before or after exercise.
2. (US) A similar garment worn for warmth.
3. One who sweats (produces sweat).
4. One who or that which causes to sweat.
5. A diaphoretic remedy.
6. (historical) A middleman who subcontracted piece work in the tailoring trade.
7. (archaic) One who sweats coins, i.e. removes small portions by shaking them.
8. (Britain, obsolete) A London street ruffian in Queen Anne's time who prodded weak passengers with his sword-point.

(for sense 1): sweatshirt

(for sense 2): jumper, pullover, jersey, cardigan, wooly

(for sense 3): perspirer

(for sense 4): exploiter