waterproof

UK: /ˈwɔːtə^rpruːf/

US: /ˈwɔtɚˌpruf, ˈwɑtɚ/

US: (wô′tər pro̅o̅f′, wot′ər-)

WordReference Random House Learner's Dictionary of American English © 2025

wa•ter•proof /ˈwɔtɚˌpruf, ˈwɑtɚ/   adj. 

1. that does not allow water to penetrate:
   a waterproof raincoat.

v. [~ + object]

2. to make waterproof.

wa•ter•proof•ing, n. [uncountable]

WordReference Random House Unabridged Dictionary of American English © 2025

wa•ter•proof  (wô′tər pro̅o̅f′, wot′ər-), adj. 

1. impervious to water.
2. rendered impervious to water by some special process, as coating or treating with rubber:
   a waterproof hat.

n. 

3. British Terms [Chiefly Brit.] a raincoat or other outer coat impervious to water.
4. any of several coated or rubberized fabrics that are impervious to water.

v.t. 

5. to make waterproof.

• water + -proof 1730–40

wa′ter•proof′er, n. 
wa′ter•proof′ness, n. 

Collins Concise English Dictionary © HarperCollins Publishers::

waterproof / ˈwɔːtəˌpruːf/ adjective

1. not penetrable by water
   Compare water-repellent, water-resistant

noun

1. a waterproof garment, esp a raincoat

verb (transitive)

1. to make (a fabric, item of clothing, etc) waterproof