[more unprofessional; most unprofessional]
: not having or showing the experience, skill, etc., that is expected or appropriate in a person who is trained to do a job well
She was accused of unprofessional conduct.
He ran the firm in an unprofessional manner.
Typos look very unprofessional.
— unprofessionalism /ˌʌnprəˈfɛʃənəˌlɪzəm/ noun [noncount]
He was criticized for his unprofessionalism.
— unprofessionally /ˌʌnprəˈfɛʃənəli/ adverb
She acted unprofessionally.