noun
moisture permeability
Technical term used in materials science, textiles, and packaging to describe how well a material allows moisture vapor to pass through.
このジャケットは透湿性が高いので、蒸れにくい。
This jacket has high moisture permeability, so it doesn't get stuffy easily.
透湿性フィルムは食品包装によく使わ
Moisture-permeable films are often used in food packaging.
通気性 refers to air permeability, whereas 透湿性 specifically refers to moisture vapor transmission.
Compound of 透 (to pass through), 湿 (moisture), and 性 (property). The exact historical derivation is uncertain, but the term is a modern technical coinage.