Meaning

adjective not producing or capable of producing

adjective not producing desired results

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- Proto-Indo-European *per-der.? Proto-Indo-European *per-der.? Proto-Indo-European *pér Proto-Indo-European *-o Proto-Indo-European *pró Proto-Indo-European *pro- Proto-Italic *pro- Late Latin prō- Proto-Indo-European *dewk- Proto-Indo-European…

Etymology from Wiktionary, CC BY-SA 3.0