Adjective: incontestible
- Incapable of being contested or disputed
"The DNA evidence provided incontestible proof of his innocence";
- incontestable
See also: bulletproof, demonstrable, demonstrated, inarguable, incontrovertible, ironclad, unanswerable, unarguable, unassailable, unquestionable, unshakable, unshakeable, watertight