The most common Korean word for “reason” is 이유 (iyu). 「reason」는 한국어로 이유.
Learn 이유 free — flashcards, audio and review →「이유」 단어장으로 무료로 외우기Words and levels: TOPIK I essentials (National Institute of Korean Language standard curriculum, KOGL Type 1) · examples: Cheesepotato