ungrateful /ʌnˈɡɹeɪtfəl/adjective 2noun 1forms 3 adjective2 •Not grateful; not expressing gratitude.“It seems to delight you to think that you are to leave Paris, and that we shall not see each other for months, perhaps. Tarzan, you are a most ungrateful beast!” and D’Arnot laughed. — 1913 •Disagreeable, repellent, unpleasant.If any care for what is here Survive in spirits render’d free, Then are these songs I sing of thee Not all ungrateful to thine ear. — 1850 noun1 •A person who fails to show gratitude; an ingrate. formsungratefuls · more ungrateful · most ungrateful