inefficient

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.

inefficient workers

an inefficient administrator

A person who cannot or does not work efficiently.

Two men were put to work who could not set their looms; a third man was taken on who helped the inefficients to set the looms. The other weavers thought this was a breach of their union rules and 18 of them struck […]

A general shaking up of the workers from top to bottom would result; and when equilibrium had been restored, the number of the inefficients at the bottom of the Abyss would have been increased by hundreds of thousands.