rainproof

[ reyn-proof ]

/ ˈreɪnˌpruf /

impervious to rain; keeping out or unaffected by rain: a rainproof cover; a rainproof coat.

to make rainproof.

Origin of rainproof

First recorded in 1825–35; rain + -proof

Cravenette—Cloths treated and finished before weaving by an improved process which renders them rainproof.

Textiles and Clothing |Kate Heintz Watson
A more suitable and rainproof roof could scarcely be designed.

Argentina From A British Point Of View |Various
We hasten to the trusty car and are soon ensconced beneath its rainproof coverings.

In Unfamiliar England |Thomas Dowler Murphy
No one would cavil at that term as applied to Whitman—yet one must not forget the “rainproof coat.”

The Vagabond in Literature |Arthur Rickett

An outer covering that is rainproof and non-absorbent avoids the absorption of water and the consequent increase of weight.

Flying the Atlantic in Sixteen Hours |Arthur Whitten Brown

rainproof

/ (ˈreɪnˌpruːf) /

Also: raintight (of garments, materials, buildings, etc) impermeable to rainwater

(tr) to make rainproof