The word "低头" is formed by directly combining two characters, each representing a core concept: "低" (dī), which means "low", and "头" (tóu), which means "head". Its formation is purely visual and conceptual, creating a literal image of the physical act of lowering one's head. This concrete image then naturally extends to embody associated metaphorical actions and states, such as showing submission, bowing in respect, or becoming engrossed in a task, making the compound a direct pictorial metaphor for the gesture and its implied meanings.