deficiency

A lack of something needed, or having less of it than is necessary.

• The test showed an iron deficiency.
• A poor diet can cause vitamin deficiencies.
• They found a serious deficiency in the safety system.

How to use it: a deficiency in something (The report identified a deficiency in staff training.); a deficiency of something (A deficiency of iron can make you feel tired.)

Similar words: lack, shortage

Opposites: excess

Common phrases: vitamin deficiency, iron deficiency, deficiency in something