Antonyms of adj watertight

2 senses of watertight

Sense 1
watertight -- (not allowing water to pass in or out)

INDIRECT (VIA tight) -> leaky -- (permitting the unwanted passage of fluids or gases ; "a leaky roof"; "a leaky defense system")

Sense 2
unassailable, unshakable, watertight, bulletproof -- (without flaws or loopholes; "an ironclad contract"; "a watertight alibi"; "a bulletproof argument")

INDIRECT (VIA incontestable) -> contestable -- (capable of being contested)

Similarity of adj watertight

2 senses of watertight

Sense 1
watertight -- (not allowing water to pass in or out)
       => tight (vs. leaky) -- (of such close construction as to be impermeable; "a tight roof"; "warm in our tight little house")

Sense 2
unassailable, unshakable, watertight, bulletproof -- (without flaws or loopholes; "an ironclad contract"; "a watertight alibi"; "a bulletproof argument")
       => incontestable (vs. contestable), incontestible -- (incapable of being contested or disputed)