WordofTheDay.US

unthankful

adjective

Origin

From Middle English unthankful, from Old English unþancful, unþancfull, unġeþancfull (“unthankful, ungrateful”), equivalent to un- + thankful. Cognate with Old High German undankfol (“unthankful, ungrateful”).

From Wiktionary, via Kaikki.org (CC BY-SA)