ingrate
Word family (noun) gratitude ≠ ingratitude ingrate (adjective) grateful ≠ ungrateful (adverb) gratefully
From Longman Dictionary of Contemporary Englishingratein‧grate /ɪnˈɡreɪt, ˈɪŋɡreɪt $ ˈɪŋɡreɪt/ noun [countable] formal THANKan ungrateful personOrigin ingrate (1400-1500) Latin ingratus, from gratus “grateful”