The word 生气 is formed through a vivid conceptual metaphor where 生 ("to give birth/generate") and 气 ("air/energy/vapor") are combined. It visually depicts the inner physical sensation of anger as one's vital energy or "life force" being stirred up, agitated, and rising within the body, like steam building in a pot, until it seeks expression. This formation captures the emotion not as an abstract state, but as a dynamic, almost tangible phenomenon of generated and pressurized energy.