을 입고

wearing

→ 을
phrase Common #2,880
wearing Usually refers to wearing clothes, but 입다 can also mean to suffer an injury, such as a burn or gunshot wound. 을 is an object marker attached to the preceding noun.
KO: 그는 흰 옷을 입고 있어요.
EN: He is wearing white clothes.

비행기 에선 작업복을 입고 있었소

I was wearing work clothes on the plane.

— 어 퓨 굿 맨 (1992)