欠・缺|けつketsu[1]atamadaka (head-high)

1. nounlack; deficiency; vacancy
2. nounabsence; non-attendance

• Synonym不十分ふじゅうぶんNeutralRefers to something being insufficient or inadequate, as in 「準備が不十分」. It stresses a degree falling short, while 「欠」 stresses that a particular item is missing.
• Synonym欠乏けつぼうNeutralRefers to shortages of material things like nutrients or supplies, as in 「ビタミン欠乏」「酸素欠乏」. It stresses being short to the point of not meeting needs.
• Synonym不足ふそくNeutralThe most versatile and common everyday word for being short of something; it can also express dissatisfaction. For ordinary 'not enough', this is the usual word.
• Synonym欠如けつじょNeutralFor something that ought to be there being missing or lacking, especially abstract qualities, as in 「常識の欠如」. It stresses the absence of a quality.
• Synonym不備ふびNeutralRefers to procedures or preparations being incomplete, as in 「書類の不備」. It stresses oversights and omissions.
• Related不全ふぜんNeutralRefers to something not functioning fully; mostly a medical term as in 「心不全」. It stresses incomplete or impaired function.
• Related不完全ふかんぜんNeutralMeans incomplete or flawed, as in 「不完全燃焼」. It stresses incompleteness — something not whole.
• Related手薄てうすNeutralDescribes thin manpower or weak defenses, as in 「警備が手薄」. It stresses strength or staffing being too thin.
• Related欠失けっしつNeutralA specialist term for something being lost or missing, used mainly in genetics as in 「遺伝子欠失」.
• Antonym足るたるWrittenAntonym: to be sufficient or worthy, as in 「信頼に足る」. A written, formal verb that stands opposite to 「欠」 in the sense of lacking.
• Antonym完かんNeutralAntonym: completion or the end, as the 「完」 printed at the close of a serialized story. It stands opposite to 「欠」 in wholeness versus incompleteness.

「欠」 is mostly a combining element for lack or absence, as in 「欠員」, 「欠席」 and 「欠を補う」. For ordinary 'not enough' use 「不足」, for severe shortages 「欠乏」, and for missing qualities 「欠如」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 必要ひつようなものが足たりないこと
2. いるべき場所ばしょにいないこと