The term **死党 (sǐdǎng)** is formed through metaphorical compounding, combining the character **死 (sǐ)**, meaning "death," with **党 (dǎng)**, meaning "faction" or "party." Literally, it suggests a "death-bound faction" or "until-death group," but its actual meaning is entirely figurative, describing an exceptionally close, loyal, and inseparable friendship that implies unwavering solidarity and commitment, as if the friends are bound together for life. This formation leverages hyperbole and the concept of ultimate sacrifice to intensify the notion of absolute trust and camaraderie, commonly used in informal contexts to refer to one's very best friends or sworn allies.