Synonyms for watertight

Adjective

1. leakproof, watertight, seaworthy (vs. unseaworthy)

usage: having no leaks

2. watertight, tight (vs. leaky)

usage: not allowing water to pass in or out

3. ironclad, unassailable, unshakable, watertight, bulletproof, incontestable (vs. contestable), incontestible

usage: without flaws or loopholes; "an ironclad contract"; "a watertight alibi"; "a bulletproof argument"