Source : Webster's Revised Unabridged Dictionary (1913)

Nonprofessional \Non`pro*fes"sion*al\, a.
   Not belonging to a profession; not done by, or proceeding
   from, professional men; contrary to professional usage.

Source : WordNet®

nonprofessional
     adj : not professional; not engaged in a profession or engaging in
           as a profession or for gain; "the nonprofessional wives
           of his male colleagues"; "nonprofessional actors" [ant:
            {professional}]