背心 (bèi xīn): vest, undershirt

It's very hot today; he just wore a white vest and shorts when he went out.

Grandpa always wears a gray cotton vest in winter, saying it's both warm and convenient for moving around.

She likes to wear a black sports vest when she goes to the gym because it's more comfortable when exercising.

This vest shrank after being washed a few times, and now it feels a bit tight when worn.

Mom knitted me a red wool vest and told me to wear it under my school uniform in winter.

On the construction site, workers must wear safety vests to enter the construction area.