The most common Korean word for “smile” is 웃다 (utda). There is one more word with a similar meaning — compare them below. 「smile」는 한국어로 웃다.
to laugh; to smile
TOPIK 1 · verb
Words and levels: TOPIK I essentials (National Institute of Korean Language standard curriculum, KOGL Type 1) · examples: Cheesepotato