any fabric impervious to water
"The hikers put on their new waterproof jackets before stepping into the rain, knowing the tough synthetic fabric was completely impervious to water."
a water-resistant coat
"She wore her waterproof coat to keep dry during the sudden rainstorm."
A substance or preparation for rendering cloth, leather, etc., impervious to water.
"The hiker applied a special waterproof to his boots before setting out in the rain."
In plain English: A waterproof is not an object but rather describes something that cannot be soaked through by water.
"The watch came with a waterproof that protected his phone from rain."
To make waterproof or water-resistant.
"Before hiking in the rain, she treated her canvas tent with a special spray to waterproof it completely."
In plain English: To waterproof something means to treat it so that water cannot get inside and cause damage.
"The heavy rain did not waterproof my new hiking boots because they were already soaked through."
Usage: Use the verb form when describing the action of treating a material so it cannot be soaked through by liquid. This is distinct from using "waterproof" as an adjective to describe something that already possesses this quality.
not permitting the passage of water
"The new raincoat is completely waterproof, so no moisture can pass through it even during a heavy downpour."
Unaffected by water.
"The new raincoat is completely waterproof, so it stays dry even during a heavy downpour."
The word waterproof is a compound of the English words water and -proof, which literally means "not allowing passage." It was formed by combining these elements to describe materials that resist being soaked through.