1. Someone who engages in an art, science, study, or athletic activity for pleasure rather than for payment or as a pastime rather than as a profession: An amateur is someone who primarily loves or is greatly interested in doing something without being paid to do it.

Mrs. Flower was an amateur in her hobby of gardening, and she knew quite a lot about vegetables and flowers.
2. In sports, an athlete who has never accepted money, or who accepts money under restrictions specified by a regulatory body, for participating in a competition: Tom loved football and was an amateur who often played in football games in town.
3. Etymology: from French amateur, "lover of" from Old French which came from Latin amatorem, amator, "lover" from amatus, amare, "to love".