こう 効がある LinksSentence search for 効があるSentence search for こうがあるSentence search for 効が有るKanji details for 効Edit in JMdict Expressions (phrases, clauses, etc.), Godan verb with 'ru' ending (irregular verb)1. to be beneficial to; to be efficaciousOther forms効が有る 【こうがある】 Discussions Log in to talk about this word.