prefix
-proof; -resistant
Productive prefix used in technical and everyday compounds to indicate resistance to something, such as water, fire, or chemicals.
See also: 耐アルカリ性
この時計は耐水性があります。
This watch is water-resistant.
耐熱ガラスは高温でも割れにくい。
Heat-resistant glass is hard to break even at high temperatures.
From the kanji 耐 (endure, withstand), used as a prefix in compounds. The reading たい is the on'yomi.