Translation guide
The English word "deficiency" refers to a lack or shortage of something needed, or a weakness or flaw. In Japanese, the best translation depends on whether you mean a shortage of a resource, a nutritional or medical lack, a personal weakness, or a formal defect.
Use when referring to an insufficient amount of a resource, supply, or necessary element.
The most common and versatile word for a shortage or insufficiency. Used for tangible things like money, staff, or materials, as well as abstract things like sleep or exercise.
The project is delayed due to a deficiency of funds.
Sleep deficiency is bad for your health.
A more formal or technical term for a severe lack or scarcity, often used in medical, nutritional, or economic contexts.
Vitamin D deficiency weakens bones.
Water deficiency has become a serious problem.
Refers specifically to the amount that is lacking; the shortfall or deficit.
The deficiency will be covered from next month's budget.
Use when talking about a lack of a specific vitamin, mineral, or substance in the body, or a medical condition caused by such a lack.
The standard medical term for a deficiency disease or condition, such as iron deficiency anemia.
I was diagnosed with iron deficiency.
A casual, everyday way to say you are not getting enough of something. Often used in conversation.
I might have a vegetable deficiency.
Use when referring to a shortcoming in someone's character, ability, or performance.
A general word for a fault, defect, or weak point. Can be used for people, plans, or objects.
His only deficiency is his short temper.
Literally 'weak point', often used for a vulnerability or area where someone or something is not strong.
Often used in contrast to 長所 (strengths) when evaluating a person's character or a product's features.
Use in legal, technical, or quality-control contexts to indicate a failure to meet a standard or requirement.
Refers to an inadequacy, defect, or something being incomplete, often used for documents, systems, or preparations.
The application was not accepted due to deficiencies.
Deficiencies were found in the security.
A defect or flaw, often used for manufactured products, systems, or genetic defects. Implies something is faulty.
不足 is the everyday word for 'not enough'. 欠乏 is stronger and more formal, implying a serious or critical lack, often used in medical or economic contexts. For general use, 不足 is safer.
staff shortage
English often uses 'deficiency' as a standalone noun, but Japanese usually requires a compound or a phrase specifying what is lacking. For example, 'iron deficiency' is 鉄欠乏症 or 鉄分不足, not just 欠乏.
The report highlighted several deficiencies in the system.
Vitamin C deficiency can cause scurvy.
He has a deficiency in communication skills.
Calcium deficiency can cause osteoporosis.
最近、鉄分が足りない気がする。
Lately I feel like I have an iron deficiency.
This plan has several deficiencies.
数学が彼の弱点だ。
Math is his deficiency.
She is trying to overcome her deficiencies.
In the interview, I was asked about my strengths and deficiencies.
その車には設計上の欠陥がある。
That car has a design deficiency.
Data was lost due to a software deficiency.