1) Amateur 2) Amateurish 3) Bush-league 4) Inexpert 5) Unskilled 1) Amateur 2) Amateurish 3) Clumsy 4) Crude 5) Incompetent 6) Inexpert 7) Nonprofessional 8) Not belonging to a profession 9) Not professional 10) Shoddy 11) Slapdash 12) Slipshod 13) Sloppy 14) Substandard 15) Unskilled 
[adj] - not characteristic of or befitting a profession or one engaged in a profession
unprofessional 1. Below or contrary to the standards expected in a particular profession. 2. Not characteristic of, or befitting, a profession or one engaged in a profession.
adjective not characteristic of or befitting a profession or one engaged in a profession; `described in unprofessional language so that high school students could understand it`; `was censured for unprofessional conduct`; `unprofessional repairs`
not professional; not pertaining to or characteristic of a profession. · at variance with or contrary to professional standards or ethics; not befitting members of a profession, as language, behavior, or conduct. · not belonging to a profession; nonprofessional. · not done with professional competence, as a play staged or an opera...