ゆうこう 有効 Common word JLPT N3 LinksSentence search for 有効Sentence search for ゆうこうKanji details for 有 and 効Edit in JMdict Na-adjective (keiyodoshi), Noun1. valid; effectiveAntonym: 無効Noun2. yuko (judo)Martial arts Discussions Log in to talk about this word.