ingratitude UK /ɪnˈɡɹætɪtjuːd/US /ɪnˈɡɹætɪtud/ noun1 •A lack or absence of gratitude; thanklessness.“Mrs. Yule's chagrin and horror at what she called her son's base ingratitude knew no bounds ; at first it was even thought that she would never get over it.[…]” — 1904 formsingratitudes