As a noun inefficiency
is lack of efficiency or effectiveness.
As an adjective inefficient is
Lack of efficiency or effectiveness.
Not efficient; not producing the effect intended or desired; inefficacious; as, inefficient means or measures.
Incapable of, or indisposed to, effective action; habitually slack or remiss; effecting little or nothing; as, inefficient workers; an inefficient administrator.
- Celery is an inefficient food.
- Jessica was terribly inefficient at cleaning, so her brother usually had to clean the whole room.