Meaning

noun a factor whose effects cannot be accurately assessed

adjective difficult or impossible to evaluate with precision

originEtymology tree Proto-Indo-European *né Proto-Indo-European *n̥- Proto-Italic *n̥- Latin in-bor. Middle English in- English im- English ponder Proto-Indo-European *-tḗr Proto-Indo-European *-dʰlom Proto-Indo-European *-dʰlis Proto-Italic *-ðlis Latin -bilis Latin -ābilis Old French -ablebor. Middle English -able English -able English ponderable English imponderable From im- + ponderable.

Etymology from Wiktionary, CC BY-SA 3.0