12 letters · 18 points in Scrabble
adjective not liable to being annulled or voided or undone
originEtymology tree Proto-Indo-European *né Proto-Indo-European *n̥- Proto-Italic *n̥- Latin in-bor. Middle English in- English in- English defeasible English indefeasible From in- + defeasible.
Etymology from Wiktionary, CC BY-SA 3.0