unassailable

absolute conclusive indisputable infallible irrefutable undeniable unequivocal

ascertained authoritative clear confirmable definite demonstrable destined determined establishable evident firm fixed genuine guaranteed hard having down pat in the bag inarguable incontestable incontrovertible indubitable known on ice plain positive predestined provable real reliable safe salted away set sound supreme sure sure thing true trustworthy unambiguous undisputable undoubted unerring unmistakable unquestionable verifiable

disputable doubtful dubious imperfect indefinite questionable refutable uncertain unsure vague