inefficient /ˌɪn.ɪˈfɪʃ.ənt/adjective 2noun 1forms 3 adjective2 •Not efficient; not producing the effect intended or desired; inefficacious.Celery is an inefficient food. •Incapable of, or indisposed to, effective action; habitually slack or unproductive; effecting little or nothing.Jessica was terribly inefficient at cleaning, so her brother usually had to clean the whole room. noun1 •A person who cannot or does not work efficiently. formsinefficients · more inefficient · most inefficient