"宰客" literally combines 宰 (zǎi), meaning 'to slaughter'—originally used for animals like pigs or chickens—and 客 (kè), meaning 'customer' or 'guest'. This vivid metaphor evokes the image of a merchant treating customers like livestock to be slaughtered: i.e., overcharging, deceiving, or exploiting them financially. It’s a colloquial, slightly humorous but strongly negative term widely used in spoken and informal written Chinese.

The phrase is most common in contexts involving tourism, street markets, taxis, or small vendors where prices are unregulated or bargaining is expected. It carries moral disapproval and implies unfairness rather than mere high pricing—it suggests intentional deception or abuse of a customer’s lack of local knowledge or urgency. While not formal, it appears frequently in news reports about consumer rights violations and online reviews warning others about dishonest businesses.