11 letters · 17 points in Scrabble
adjective not capable of being precisely or readily described; not easily put into words
originEtymology tree Proto-Indo-European *né Proto-Indo-European *n̥- Proto-Germanic *un- Proto-West Germanic *un- Old English un- Middle English un- English un- English definable English undefinable From un- + definable.
Etymology from Wiktionary, CC BY-SA 3.0