Synonyms for Nonprofessional:

adj.

amateur (adjective)
unprofessional, novice, unskilled, primitive, amateur, incompetent, inexperienced.
not professional (adjective)
amateur, lay.

n.

dabbler, ability, Smatterer, uninitiate. amateur (noun)
neophyte, dilettante, beginner, apprentice, initiate, layman, greenhorn, lay person.
layperson (noun)
layman, dilettante, dabbler.
nonprofessional (noun)
lay, amateur, unpaid, recreational.

Other synonyms:

Smatterer. dabbler. Other relevant words:
unpaid, dabbler, amateur, ability, recreational, uninitiate, lay, Smatterer.