apodictic

authoritative flawless foolproof unbeatable

acceptable accurate agreeable certain correct effective effectual efficacious efficient exact faultless handy helpful impeccable incontrovertible inerrable inerrant omniscient perfect positive reliable satisfactory satisfying sure surefire true trustworthy undeceivable unfailing unimpeachable unquestionable useful

erring fallible faulty imperfect

indisputable ironclad unassailable undeniable

accurate can bet on it certain double-checked evident final inarguable incontestable incontrovertible indubitable invincible irrebuttable irrefragable irresistible nof ifs ands or buts obvious odds-on positive proven set sure unanswerable unimpeachable unquestionable

disputable indefinite

doubtful dubious questionable refutable uncertain