A potioneer, also known as a potion-brewer or potion-maker, is a witch or wizard who makes potions for a living. meaning that their primary source of income comes from making potions or in someway related to potions in general. This could include working as a professional brewer, studying or inventing potions, or teaching potions as a subject at a wizarding school.
A person who teaches potions is sometimes known as a potions master, one who has achieved a N.E.W.T. in the subject.