Also found in: Dictionary, Thesaurus, Medical, Legal, Acronyms, Encyclopedia, Wikipedia.
in (one's) birthday suit
Completely naked. (Alludes to the fact that one's "suit" is nothing at all when born.) I have a recurring nightmare where I'm walking through school in my birthday suit. As kids, we had no problem going swimming together in our birthday suits.
*in one's birthday suit
Fig. naked; nude. (In the "clothes" in which one was born. *Typically: be ~; get [into] ~.) I've heard that John sleeps in his birthday suit. We used to go down to the river and swim in our birthday suits.
Nakedness, as in The doorbell rang, and here I was in my birthday suit. In 18th-century Britain this term originally referred to the clothes one wore on the king's birthday. Later it was jocularly transferred to bare skin, alluding to the condition of a newborn baby.
in your birthday suitINFORMAL
If you are in your birthday suit, you are not wearing any clothes. I could go out there in my birthday suit and nobody would even notice. Note: This expression is used humorously.
in your birthday suitnaked. humorous
in/wearing your ˈbirthday suit(informal, humorous) wearing no clothes; naked: The towel fell off, and there he was in his birthday suit!
Wearing no clothes. People said to be in their birthday suit are as naked as the day they were born.