Synonyms for ungrateful
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thankless, unthankful, selfish, lacking in appreciation, unappreciative, grasping, demanding, self-centered, unmindful, forgetful, heedless, careless, insensible, dissatisfied, grumbling, unnatural, faultfinding, oblivious.
Antonyms thankful*, grateful obliged.
See ungrateful in Webster's New World Roget's A-Z Thesaurus II
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