One who deals or metes out anything.
A particular type of stock broker or trader.
One who deals in goods, especially automobiles; a middleman.
A drug dealer, one who peddles illicit drugs.
The person who deals the cards in a card game.
One who or that which helps something to happen.
One who encourages a bad habit in another (typically drug addiction) by their behaviour.
One who gives someone else the power to behave in a certain way.