の反対語 based on guesswork

genuine actual concrete real effective true certified existent factual authentic confirmed corroborated definite documented verified attested considerable proven substantial verifiable clear good indisputable undeniable realistic significant unquestionable veritable absolute essential fundamental tangible categorical certain established indubitable substantiated positive bona fide substantive

empirical practical empiric observational observed pragmatic experiential objective seen existential experimental heuristic real actual applied experient factual firsthand realistic first-hand hands-on

based on hearsay baseis baseless baselessly baselessness baseline based on fiction based on based base class base-born baseborn