Word Detail

The Japanese word 有効 (ゆうこう, *yuukou*) generally translates to "valid," "effective," "in effect," "available," or "good." It implies that something is legitimate, functional, capable of achieving a desired result, or currently in operation. The specific nuance depends on the context. 有効 can refer to things such as documents, medicines, policies, or even a person's strategy.

⚫︎このパスポートは有効です。 Translation: This passport is valid. ⚫︎この薬はインフルエンザに有効ですか？ Translation: Is this medicine effective against the flu? ⚫︎契約は来月から有効になります。 Translation: The contract will be in effect from next month.

有効 is a versatile word used in formal and informal contexts. It's used to describe the state of something being functional, currently active, or having legal standing. You can use it when discussing deadlines, regulations, treatments, or the efficacy of something. The word itself is relatively formal, but is widely used and easily understood.

有効 is primarily written in kanji, with the reading in hiragana: 有効 (ゆうこう). There are no common alternative writings or variations in the okurigana. The conjugations of 有効 follow the standard rules of な-adjectives. 有効な (yuukou na) - valid, effective (adjectival form) 有効に (yuukou ni) - effectively, validly (adverbial form) 有効性 (yuukousei) - effectiveness, validity (noun form)

⚫︎ 妥当 (だとう, *datou*) - valid, appropriate ⚫︎ 効果的 (こうかてき, *koukateki*) - effective ⚫︎ 正しい (ただしい, *tadashii*) - correct, right ⚫︎ 効く (きく, *kiku*) - to be effective (verb) ⚫︎ 有効期限 (ゆうこうきげん, *yuukou kigen*) - Expiration date

⚫︎ 無効 (むこう, *mukou*) - invalid, ineffective ⚫︎ 無効な (むこうな, *mukouna*) - invalid, ineffective (adjectival form) ⚫︎ 役に立たない (やくにたたない, *yakunitatanai*) - useless, not helpful

この割引クーポンは今月末まで有効です。 ・Translation: This discount coupon is valid until the end of this month. ・Explanation: The sentence clarifies that the coupon's usability is limited by a time constraint.

その治療法は、まだ有効性が確認されていません。 ・Translation: That treatment's effectiveness has not yet been confirmed. ・Explanation: This sentence discusses the lack of proven effectiveness of a medical treatment. It uses the noun form 有効性 (effectiveness)

The word 有効 is a combination of two kanji: 有 (ゆう, *yuu*), meaning "to have," "exist," or "possess," and 効 (こう, *kou*), meaning "effect," "efficacy," or "result." Thus, the word conveys the idea of something that "has an effect" or "is effective."