一日一成语【279】in one’s birthday suit 一丝不挂；裸露

in one’s birthday suit
[俗]一丝不挂；裸露

I guess he didn’t know I was in the house. When I walked into the living room, he was just standing in his birthday suit.
我猜他当时并不知道我在屋里。我走进起居室时，他正一丝不挂地站在那儿!

注解：
birthday意指生日，suit意指套装；to be in one’s birthday suit, birth出生，birthday出生那天，人出生时什么都不穿，因此，喻指一丝不挂，裸露的样子。