IPA: /ɪnˈɡrætɪtjuːd/
KK: /ɪnˈɡrætɪtud/
A feeling or state of not being thankful or appreciative for what someone has done for you.
Her ingratitude was surprising after all the help he had given her.
Ingratitude → It is formed from "in-" (meaning not) and "gratus" (meaning pleasing or thankful) and "-tude" (a suffix indicating a state or condition). The word "ingratitude" refers to the state of being not thankful or ungrateful.
Think of 'not' ('in-') being combined with 'thankful' ('gratus') to remember that ingratitude means a lack of thankfulness.