The compound "stone-cold" is a native English formation, combining two elemental words of Germanic origin. "Stone," from Proto-Germanic stainaz, has long been used metaphorically to denote hardness, immovability, and lifelessness. "Cold," from Proto-Germanic kaldaz, describes the absence of heat. The pairing leverages the intrinsic, absolute coldness of stone—a material that does not generate warmth—to create a powerful intensifier. Thus, "stone-cold" evolved from a literal description of an object's temperature to an emphatic idiom meaning "completely cold" or, figuratively, "utterly devoid of emotion or warmth," perfectly capturing the unyielding and inert qualities associated with stone.

Structure: stone (stone) + cold (cold) stone: From Old English stān, meaning "rock, stone." In this compound, it functions as an intensifier. cold: From Old English cald/ceald, meaning "of low temperature, not warm." It is the core adjective being modified.