Deficiency (noun)

1. A lack or shortage of something required or desirable.
2. A flaw or weakness in something.

Origin:

Late middle english: from old french deficient, from latin deficient- "failing", from the verb deficere, from de- "away from" + facere "do".

Examples:

1. Vitamin D deficiency is common in people who don't get enough sun exposure.
2. His proposal was rejected due to a deficiency in its research and planning.
3. The report highlighted the deficiency in the country's education system.
4. Her language skills showed a deficiency in grammar and vocabulary.
5. The doctor detected a deficiency in his blood and prescribed him some supplements.