see-through from wetness
Describes clothing that becomes transparent or revealing when wet. Often used in contexts like wet T-shirt contests or accidental exposure.
白いシャツが濡れ透けになって、下着が見えてしまった。
The white shirt became see-through from the wetness, and my underwear was visible.
プールから上がったら、水着が濡れ透けで恥ずかしかった。
When I got out of the pool, my swimsuit was see-through from being wet, which was embarrassing.
Compound of 濡れ (nure, 'wetness', from 濡れる) and 透け (suke, 'see-through', from 透ける). The exact origin is uncertain, but it likely emerged in modern colloquial Japanese.