water-proof

Adjective

waterproof (comparative more waterproof, superlative most waterproof)

1. (broadly, but common) Resistant to the effects of water.

   Synonyms:

   water-resistant

2. (strictly) Made of or covered with material that doesn't allow water in; impervious to water and immune to its effects.
   • The captain did a safety drill. This covered where the emergency position-indicating radio beacon (EPIRB) was located, how to make a mayday call, and where the fire extinguishers were. A crew member demonstrated how to put on an immersion suit. These survival suits are waterproof full-body garments...2025 October 21, Rose George, “‘I knew in my head we were dying’: the last voyage of the Scandies Rose”, in The Guardian

   Synonyms:

   waterfast, watertight

3. (figuratively) Incapable of failing; unassailable.
   • The only waterproof plan and the one increasingly adopted by leading trades is the consolidation of the interests of all parties in a scheme of amalgamation.1931, The British Clay Worker
4. (uncommon) Not dependent on an aquatic environment to live; thus, able to live on dry land, or at least in a semiaquatic environment.
   • At the time the Burgess Shale was laid down, life on land was pretty unexciting – there were a few primitive clubmosses and liverworts growing in wet areas near water, but little else. There would also have been a strand-line of washed-up plants and animals, edible detritus that was tantalisingly...2015, Dave Goulson, A Buzz in the Meadow: The Natural History of a French Farm, Picador, →ISBN, pages 24-25

See all 7 meanings of waterproof