What does waterproof mean?
Waterproof is an adjective describing something that prevents water from passing through or affecting it, such as clothing, fabric, coatings, cases, or electronic devices. As a verb, it means to make an object waterproof, usually by adding a protective material or seal. As a countable noun, especially in British English, “a waterproof” means a raincoat or similar outer garment. The word is absolute in ordinary use: it suggests a reliable barrier against water, whereas “water-resistant” indicates only partial or limited protection. That distinction matters in technical and commercial descriptions, where the exact performance of a material may depend on time, depth, pressure, and the condition of its seams. In everyday contexts, waterproof often suggests practical resilience rather than total immunity to water, so context determines how strong the claim is. The compound is especially useful because it combines the familiar substance with the older idea of being “proof” against something, making the meaning immediately clear to English speakers.
That prevents water from passing through or affecting something.
"The phone has a waterproof case that protects it when submerged."
The term expresses a strong claim and is often used with clothing, materials, coatings, containers, and electronic devices.
To make something resistant or impervious to water.
"They waterproofed the wooden shed with a clear protective coating."
Usually transitive; “waterproof something” or “something is waterproofed.”
A waterproof garment or protective covering, especially a raincoat.
"He took his waterproof with him because the weather had turned wet."
Chiefly British and common in everyday usage.
Plural in the sense of waterproof garments or coverings; the noun is chiefly used in British English.
"The shop sells waterproofs for children."
Waterproof makes a bold promise: not merely slowing the rain, but keeping the water out.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does waterproof come from?
Waterproof is an English compound formed in the early 17th century from “water” and “proof.” “Water” descends from Old English “wætter,” ultimately from a Germanic word for water, while “proof” was extended from the sense of a test or demonstration to the meaning “resistant to” or “able to withstand.” The compound later developed into a verb and, eventually, a noun denoting a waterproof garment.
Related word forms
How waterproof is actually used
Waterproof is common in both formal and informal contexts. Its claim is strong, although practical performance can be affected by wear, seams, prolonged exposure, depth, and pressure. As a noun, “a waterproof” is especially common in British English and is often an everyday term for a raincoat.
Easily confused with waterproof
Water-resistant material limits or slows the penetration of water, whereas waterproof material is expected to prevent water from passing through under specified conditions.