The term **败类** (bàilèi), meaning "scum" or "degenerate," is a compound word formed through metaphorical combination: the character **败** (bài) means "to decay, spoil, or defeat," implying something rotten or corrupted, while **类** (lèi) means "category, kind, or class." Thus, when combined, the term literally signifies **"a decayed/rotten category (of people)"**—it metaphorically identifies individuals who are considered morally corrupt or disgraceful, thereby spoiling the reputation and integrity of the larger group (such as a community, nation, or profession) to which they nominally belong.