Where did the term “Birthday Suit” come from? I know it refers to being “naked as the day your were born” but why a “suit”?
Makes sense to me - suit as in “outfit”. Your skin is the outfit you were wearing on your “birth day”. Hence birthday suit.
As far as its origin goes, Cassell’s Dictionary of Slang says only that it dates from the mid-18th century.
Your birthday suit (hey, nice suit!) is what you take off when it’s so hot, you’re gonna dance around in your bones.
That’s from Fred Allen, or maybe somebody earlier than that.