in (one's) birthday suit

in (one's) birthday suit

Completely naked. Alludes to the fact that one is born without clothing. 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.See also: birthday, suit

*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.See also: birthday, suit

in your birthday suit

INFORMALIf 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. See also: birthday, suit

in your birthday suit

naked. humorousSee also: birthday, suit

in/wearing your ˈbirthday suit

(informal, humorous) wearing no clothes; naked: The towel fell off, and there he was in his birthday suit!See also: birthday, suit, wearing