adj. 25B6; adjective
unprofessional conduct : IMPROPER, unethical, unprincipled, unscrupulous, dishonourable, disreputable, unseemly, unbecoming, indecorous; informal shady, crooked.
he accused the detectives of being unprofessional : AMATEURISH, amateur, unskilled, unskilful, inexpert, unqualified, inexperienced, incompetent, second-rate, inefficient.