watertight

adjective

wa·​ter·​tight ˌwȯ-tər-ˈtīt 

ˌwä-

1

: of such tight construction or fit as to be impermeable to water except when under sufficient pressure to produce structural discontinuity

2

: leaving no possibility of misconstruction or evasion

a watertight lease

watertightness noun

Examples of watertight in a Sentence

The doors are all watertight.

The evidence against the defendant was watertight.

Recent Examples on the Web

Shots and goals from fast breaks in the Premier League since 2018-19 Brentford set up to hit Sunderland on counter-attacks, knowing how Le Bris’ side can defend for long periods and are watertight, conceding just three in their past five before coming to south-west London. —Liam Tharme, New York Times, 8 Jan. 2026

Flooding concerns were also addressed, with the company explaining that its tunnels are designed to be watertight. —Hadley Hitson, Nashville Tennessean, 29 Sep. 2025

The deal is not yet watertight and needs to be implemented by individual members. —Mike O'Sullivan, Forbes.com, 7 Aug. 2025

The shells, which are watertight and surprisingly sturdy, usually can be completed for a project in 24 hours. —Sam Lubell, Los Angeles Times, 9 May 2025

Word History

First Known Use

15th century, in the meaning defined at sense 1

Rhymes for watertight

• acolyte
• aconite
• allanite
• alunite
• amberlite
• ammonite
• amorite
• amphitrite
• analyte
• anchorite
• andesite
• anhydrite

Kids Definition

watertight

adjective

wa·​ter·​tight ˌwȯt-ər-ˈtīt 

ˌwät-

1

: made to keep water out

a watertight compartment

2

: allowing no possibility for doubt or uncertainty

a watertight case against the accused