Adjective

Resistant to leaks; hermetic, sound; as of a dry cell battery.

* 1904, Institution of Mining and Metallurgy (Great Britain), Bulletin , Institution of Mining and Metallurgy (Great Britain) (1904), p. 22,

*:"In mining work difficult laying conditions, limited space, and movements of the ground, all combine to make the installation of a leakproof main with ordinary joints a very difficult matter."

* 1929, Victor Wilfred Pagé, Modern Aviation Engines: design-construction-operation and repair, […] , Norman W. Henley Publishing Company (1929), p. 1589,

*:"Leakproof tanks shall be provided on all airplanes for service use unless the tanks are completely protected by armor."

* 1967, Edward Locker Delmar-Morgan, Maintenance of Inboard Engines , Newnes (1967), p. 115,

*:"There are two subdivisions in the flashlight dry cell range, the ordinary cheap one and the better-quality leakproof cell."

Adjective

(en adjective)

Unaffected or unable to be affected by.

*

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Preventive of any penetration; impenetrable, impermeable, particularly of water.

Immune to damage or effect.