undocumentably

Adverb

1. In an undocumentable manner.
   • Their performative origins are undocumentably beyond our earliest record. - 2018, Odai Johnson, Ruins: Classical Theater and Broken Memory, page 37:
   • In this situation there can still exist a theatrical encouragement and accommodation of topical responses--plausible, usually private associations that playgoers inevitably if usually undocumentably make between play...