Waterproof

An item is waterproof if it is impervious to water or covered by some type of material that does not allow water to pass into or through it.

Sometimes the word water-resistant may be used as another term for waterproof.

Waterproof items may include building materials such as roofs and decks. Boats have coatings on their hulls to keep them water resistant. Some materials themselves have properties that are waterproof.. These may include plastics. Some clothing may be waterproof, having been treated as could furniture.