also: じれー
noun
A sleeveless garment worn over a shirt, often as part of formal wear or as a light outer layer. The word is a loan from French 'gilet'.
from French
彼はスーツの下にジレを着ていた。
He wore a waistcoat under his suit jacket.
このジレは軽くて、春にぴったりだ。
This vest is light and perfect for spring.