1. Not grateful; not thankful for favors; making no returns, or making ill return for kindness, attention, etc.; ingrateful.
2. Unpleasing; unacceptable; disagreeable; as, harsh sounds are ungrateful to the ear.
-- Un*grate*ful*ly, adv. -- Un*grate*ful*ness, n.
n : a lack of gratitude [syn: ingratitude] [ant: gratitude]