noun
fancy dress; costume
Refers to a costume worn for parties, events, or performances, often imaginative or themed. The term is a direct loan from English and is used in similar contexts.
ハロウィンにファンシードレスを着てパーティーに行った。
I wore a fancy dress to the Halloween party.
彼女はファンシードレスをレンタルして仮装
She rented a costume and attended the costume party.