noun-modifying (irregular)
stark naked; completely nude
Literary or emphatic expression meaning wearing not even a single thread; often used in fixed phrases like 一糸まとわぬ姿.
彼は一糸まとわぬ姿で現れた。
He appeared stark naked.
一糸まとわぬ赤ん坊の写真を撮った。
I took a photo of the completely naked baby.
From 一糸 (one thread) + まとわぬ (classical negative of まとう, to wear), literally 'not wearing a single thread'.