undeniable

Synonyms: actual beyond doubt beyond question binding certain clear compulsory evident for sure inarguable incontestable incontrovertible indisputable indubitable irrefutable manifest necessary no ifs and or buts obligatory obvious open and shut patent positive real sound sure sure thing true unanswerable unassailable undoubted unquestionable

Antonyms: contestable disputable doubted indefinite unproven