Question

ㅅ 불규칙 활용 Applies to: verb stems ending in ㅅ and the 낫다 adjective.Examples:낫다 better (than)/superior (to), to be cured짓다 to build, to name, to write잇다 to connect/link붓다 to swell, to pour긋다 to draw (a line)Exception examples: 웃다 to laugh벗다 to take off솟다 to gush out씻다 to wash앗다, 빼앗다 to snatch something from somebodyㅅ is omitted when adding a principle that begins with a vowel.낫다 → 나아요, 낫습니다, 나아서, 나으면, 나으니까, 나은짓다 → 지어요, 짓습니다, 지어서, 지으면, 지으니까, 지은잇다 → 이어요, 잇습니다, 이어서, 이으면, 이으니까, 이은붓다 → 부어요, 붓습니다, 부어서, 부으면, 부으니까, 부은긋다 → 그어요, 긋습니다, 그어서, 그으면, 그으니까, 그은Below are the examples of verbs with stems ending in ㅅ which are conjugated regularly.웃다 → 웃어요, 웃습니다, 웃어서, 웃으면, 웃으니까, 웃은벗다 → 벗어요, 벗습니다, 벗어서, 벗으면, 벗으니까, 벗은솟다 → 솟아요, 솟습니다, 솟아서, 솟으면, 솟으니까, 솟은씻다 → 씻어요, 씻습니다, 씻어서, 씻으면, 씻으니까, 씻은Despite the typical for Korean tendency to combine vowels (like 이어 → 여 or 아아 → 아), this merging does not take place in the case of irregular ㅅ. For example, 지어요 does not become 져요, and 낫아요 is never shortened to 나요.

Accepted Answer

Irregular ㅅ conjugation principle

Front	ㅅ 불규칙 활용
Back	Irregular ㅅ conjugation principle
Notes	Applies to: verb stems ending in ㅅ and the 낫다 adjective. Examples: 낫다 better (than)/superior (to), to be cured 짓다 to build, to name, to write 잇다 to connect/link 붓다 to swell, to pour 긋다 to draw (a line) Exception examples: 웃다 to laugh 벗다 to take off 솟다 to gush out 씻다 to wash 앗다, 빼앗다 to snatch something from somebody ㅅ is omitted when adding a principle that begins with a vowel. 낫다 → 나아요, 낫습니다, 나아서, 나으면, 나으니까, 나은 짓다 → 지어요, 짓습니다, 지어서, 지으면, 지으니까, 지은 잇다 → 이어요, 잇습니다, 이어서, 이으면, 이으니까, 이은 붓다 → 부어요, 붓습니다, 부어서, 부으면, 부으니까, 부은 긋다 → 그어요, 긋습니다, 그어서, 그으면, 그으니까, 그은 Below are the examples of verbs with stems ending in ㅅ which are conjugated regularly. 웃다 → 웃어요, 웃습니다, 웃어서, 웃으면, 웃으니까, 웃은 벗다 → 벗어요, 벗습니다, 벗어서, 벗으면, 벗으니까, 벗은 솟다 → 솟아요, 솟습니다, 솟아서, 솟으면, 솟으니까, 솟은 씻다 → 씻어요, 씻습니다, 씻어서, 씻으면, 씻으니까, 씻은 Despite the typical for Korean tendency to combine vowels (like 이어 → 여 or 아아 → 아), this merging does not take place in the case of irregular ㅅ. For example, 지어요 does not become 져요, and 낫아요 is never shortened to 나요.

ㅅ 낫다 Irregular Principle Stems Ending 짓다 잇다