忘恩 (wàng ēn) literally means 'to forget kindness' — 忘 (wàng) means 'to forget', and 恩 (ēn) refers to 'kindness', 'favor', or 'grace' received from others, especially when it involves sacrifice or goodwill. Together, the term describes the moral failing of disregarding or ignoring someone’s past help or benevolence.

This word carries strong negative connotations and is often used in formal, literary, or moral discourse — for example, in proverbs, essays on ethics, or criticism of disloyal behavior. It implies not just memory lapse but deliberate ingratitude, suggesting a breach of basic human decency or Confucian values like reciprocity (报恩, bào ēn). While rarely used in casual speech as a standalone noun, it frequently appears in fixed phrases like 忘恩负义 (wàng ēn fù yì, 'forget kindness and betray trust'), emphasizing deep moral failure.