缺德 literally means 'lacking virtue'—'缺' (quē) means 'to lack' or 'to be missing,' and '德' (dé) means 'virtue,' 'moral character,' or 'integrity.' Together, 缺德 functions as a vivid, colloquial adjective describing behavior that violates basic moral standards: deceitful, heartless, shameless, or deliberately harmful actions. It carries strong negative emotional weight and is often used in spoken Mandarin to express outrage, contempt, or disapproval.

This term is commonly heard in informal contexts—such as criticizing someone’s selfishness, cruelty, or betrayal—and rarely appears in formal writing or official speech. While not profane, it’s considered blunt and emotionally charged; using it toward others can sound harsh or confrontational. It's frequently paired with intensifiers like 真 (zhēn, 'really') or 太 (tài, 'too'), and sometimes used playfully among close friends—but always with awareness of tone and relationship.