忘ぼう恩おん

noun

ingratitude; thanklessness

A formal or literary term for failing to show gratitude for a kindness received. Often used in set phrases like 忘恩の徒 (ungrateful person).

• 彼かれの忘ぼう恩おんには本ほん当とうに失しつ望ぼうした。

  I was truly disappointed by his ingratitude.