noun
absorbency; hygroscopicity
Technical term used in chemistry, materials science, and product descriptions to describe the ability of a substance to absorb moisture from the air.
この素材は吸湿性が高いので、湿気の多い場所での保管に注意が必要です。
This material has high absorbency, so care is needed when storing it in humid places.
シリカゲルは吸湿性を利用して乾燥剤として使われます。
Silica gel is used as a desiccant by taking advantage of its hygroscopicity.
保湿性 means moisture retention, keeping moisture in, whereas 吸湿性 means absorbing moisture from the environment.
Compound of 吸湿 (moisture absorption) + 性 (property, -ity). The exact historical derivation is uncertain, but the kanji components are conventionally associated with the meaning.