The most common Korean word for “ninety” is 구십 (gusip). There is one more word with a similar meaning — compare them below. 「ninety」는 한국어로 구십.
Learn 구십 free — flashcards, audio and review →「구십」 단어장으로 무료로 외우기Words and levels: TOPIK I essentials (National Institute of Korean Language standard curriculum, KOGL Type 1) · examples: Cheesepotato