suru verb (special), intransitive verb
dress up as; disguise oneself as; play the role of
Used for physically dressing up or assuming the appearance of a character, often for a costume, performance, or disguise.
彼はハロウィンで吸血鬼に扮した。
He dressed up as a vampire for Halloween.
スパイは商人に扮して敵
The spy infiltrated enemy territory disguised as a merchant.