From WordNet (r) 3.0 (2006) [wn]:
amateur
adj 1: engaged in as a pastime; "an amateur painter"; "gained
valuable experience in amateur theatricals";
"recreational golfers"; "reading matter that is both
recreational and mentally stimulating"; "unpaid extras in
the documentary" [syn: amateur, recreational,
unpaid]
2: lacking professional skill or expertise; "a very amateurish
job"; "inexpert but conscientious efforts"; "an unskilled
painting" [syn: amateurish, amateur, inexpert,
unskilled]
n 1: someone who pursues a study or sport as a pastime
2: an athlete who does not play for pay [ant: pro,
professional]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Amateur \Am`a*teur"\, n. [F., fr. L. amator lover, fr. amare to
love.]
A person attached to a particular pursuit, study, or science
as to music or painting; esp. one who cultivates any study or
art, from taste or attachment, without pursuing it
professionally.
[1913 Webster]