waterproof

Short definition from Wiktionary

Adjective

1. 1
   Resistant to the effects of water.
2. 2
   Made of or covered with material that doesn't allow water in.
3. 3
   Incapable of failing; unassailable.

Verb

1. 1
   To make waterproof or water-resistant.

Noun

1. 1
   A substance or preparation for rendering cloth, leather, etc., impervious to water.
2. 2
   Cloth made waterproof, or any article made of such cloth, or of other waterproof material, as rubber; especially, an outer garment made of such material.