UNPROFESSIONAL
unprofessional
(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”
Source: WordNet® 3.1
Etymology
Adjective
unprofessional (comparative more unprofessional, superlative most unprofessional)
unbecoming of a professional; hence inappropriate in the workplace
Lacking a profession.
Noun
unprofessional (plural unprofessionals)
One who is not a professional.
Source: Wiktionary