a person who buys and sells articles without altering their condition; trader or merchant, especially a wholesaler: I got a dealer's discount on this coat.
2.
Cards.the player distributing the cards.
3.
a person who behaves or acts toward another or others in a specified manner: a plain dealer.
4.
Slang.a person who buys and sells drugs illegally.
5.
a person who buys securities for his or her account and retains them until sold to another.
O.E. dælere, agent noun from deal. Meaning "player who passes out the cards in a game" is from c.1600; meaning "one who deals in merchandise" is from 1610s. Illegal drug sense is recorded by 1920. Related: Dealership (1916).