괴상해요 · 괴상했어요 · 괴상한 (+noun)
weird, bizarre, freakish
Example
그 사람은 괴상한 옷을 입고 나타났어요.
That person showed up wearing weird clothes.
Word parts
괴 means 'weird', as in 괴물 'monster' — monster-level strange.
Good to know
More negative than 이상하다; 기이하다 sounds more neutral and literary.
Related words