noun
ingratitude
in-GRAT-ih-tood/ɪnˈɡrætɪtuːd/
Lack of thankfulness for help or kindness received.
Ignoring the thoughtful gift shows ingratitude.

Etymology
“Not” and “pleasing” underlie Latin ingratus, which also meant “ungrateful.” The quality ending turns that sense into a name for failing to acknowledge or reciprocate kindness.
In context
It was not surprising that they should hang back with faint hearts, having returned so much kindness with such deep ingratitude.
More examples
- She was surprised by their apparent ingratitude.
- The story contrasts generosity with ingratitude.
- He apologized for his ingratitude.
Forms
ingratitude
ungrateful adjective — not appreciative of kindness
Similar words
- ungratefulness
- Ungratefulness is a direct everyday equivalent for ingratitude.
- indifference
- Indifference is lack of interest; ingratitude specifically fails to appreciate a benefit received.