Englishnegligent
adjective
she claimed that her solicitor had been negligent:
careless, failing to take proper care, remiss, neglectful, lax, irresponsible, inattentive, heedless, thoughtless, unmindful, forgetful;
slack, sloppy, slapdash, slipshod;
North American derelict;
NauticalLaw barratrous;
formal delinquent;
rare disregardful, inadvertent, oscitant.
▷antonyms careful, attentive, conscientious.
negligent Oxford Dictionary of English