English
rainproof
From rain + -proof.
A compound of rain + -proof
Proto-Germanic *regną ‘rain’
Proto-West Germanic *regn ‘rain’
Old English reġn ‘rain’
Middle English reyn
English rain
Today it means
adj waterproof (for use outdoors); resistant to rain
Language periods are conventional ranges, not dates for this word.
Etymograph / rainproof