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