Synonyms of ungrateful

Adjective

1. ungrateful (vs. grateful), thankless, unthankful, unappreciative

usage: not feeling or showing gratitude; "ungrateful heirs"; "How sharper than a serpent's tooth it is / To have a thankless child!"- Shakespeare

2. ungrateful, unpleasant (vs. pleasant)

usage: disagreeable; "I will not perform the ungrateful task of comparing cases of failure"- Abraham Lincoln

Definition and meaning of ungrateful (Dictionary)