効こう力りょく

こ

う

りょ

く

Common wordJLPTN2Freq.FrequencyTop 20,000

Meanings

noun

effect; efficacy; validity; potency

Refers to the intended effect, power, or legal validity of something such as a medicine, policy, contract, or law.

この薬くすりの効こう力りょくは8時じ間かん続つづきます。
This medicine's effect lasts for eight hours.
新あたらしい法ほう律りつの効こう力りょくは来らい月げつから発はっ生せいする。
The new law will take effect from next month.

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Usage patterns

〈物もの〉が効こう力りょくを持もつfor something to have (legal) effect or validity
この契けい約やくは来らい月げつから効こう力りょくを持もつ。
This contract will take effect starting next month.
効こう力りょくを発はっ揮きするto exert one's effect or potency
新あたらしい薬くすりは数すう時じ間かんで効こう力りょくを発はっ揮きする。
The new medicine takes effect within a few hours.
効こう力りょくを失うしなうto lose effect or validity
このパスポートは来らい年ねんで効こう力りょくを失うしなう。
This passport will lose its validity next year.
効こう力りょくが生しょうじるfor (a law, rule, etc.) to come into effect
この法ほう律りつは公こう布ふから30日にち後ごに効こう力りょくが生しょうじる。
This law comes into effect 30 days after its promulgation.
効こう力りょくを停てい止しするto suspend the validity or effect (of a rule, license, etc.)
裁さい判ばん所しょはその規き則そくの効こう力りょくを停てい止しした。
The court suspended the validity of that regulation.
〈物もの〉に効こう力りょくがあるto be effective against/for something
この薬くすりは頭ず痛つうに効こう力りょくがある。
This medicine is effective against headaches.

Kanji

効merit, efficacy, efficiency
力power, strength, strong

Related words· 7

効こう果かN3
効果 is the general word for an effect or result, while 効力 stresses the power, efficacy, or legal force behind that effect.
効こう能のう
効能 is used specifically for the beneficial effect of medicine or remedies, whereas 効力 is broader and also covers legal or contractual validity.
効きき目めN1
効き目 is a casual, everyday word for how well something works (like medicine), while 効力 is more formal and can also mean legal validity.
有ゆう効こうN2
有効 is an adjective meaning 'valid' or 'effective' (used for tickets, contracts, etc.), while 効力 is the noun naming the power or validity itself.

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実じっ効こう
効力 often refers to legal force or validity, while 実効 focuses on real-world, practical effectiveness rather than formal validity.
効こう
効力 emphasizes the binding or legal potency of something (like a contract), while 効 refers more generally to a beneficial result of effort or treatment.
威い力りょくN1
効力 means the practical efficacy or validity of something like a law or medicine, while 威力 stresses its dramatic or overwhelming strength.

Opposites

無む効こうN1
無効 means 'invalid' or 'null and void', the opposite of having 効力 (legal force or effect).

Word family

自じ己こ効こう力りょく感かん
self-efficacy

Etymology

Compound of 効 (effect, efficacy) and 力 (power, strength). The exact historical derivation is uncertain, but the combination naturally yields the meaning 'effective power'.