効 力(こうりょく)

こうりょく

noun

efficacy, validity, legal force

formallegal

1. efficacy, effect, validity

The power or ability of something to produce an intended effect. Often used in legal and official contexts to mean 'validity' or 'legal force' of a document, law, or agreement.

この薬(くすり)は効力(こうりょく)がある。

This medicine is effective.

契約(けいやく)の効力(こうりょく)は来月(らいげつ)から発生(はっせい)する。

The contract takes effect starting next month.

この法律(ほうりつ)はすでに効力(こうりょく)を失(うしな)っている。

This law has already lost its validity.

Commonly used in legal, regulatory, and pharmaceutical contexts. Compared to 効果(こうか) (effect, result), 効力(こうりょく) emphasizes the inherent power or force something possesses, especially in an official or binding sense.

Common collocations

効力(こうりょく)がある — to be effective, to be valid
効力(こうりょく)を失(うしな)う — to lose validity/efficacy
効力(こうりょく)を発揮(はっき)する — to exert its effect
効力(こうりょく)が発生(はっせい)する — to take effect
法的(ほうてき)効力(こうりょく) — legal force/validity

Related Words

Compare: 効果(こうか) (effect, result)

Compare: 効(き)き目(め) (effect)

general

Added 2026.2.18 21:22 · Revised 2026.9.2 13:01

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