The word 无能为力 is formed by sequentially layering four characters to create a vivid metaphor of declining capacity. It begins with “无” (without), negating the “能” (ability) that follows, to establish a state of being unable. This inability then directly applies to the next character, “为” (to do or act), meaning one cannot undertake action. Finally, the “力” (strength or power) stands alone, disconnected and unused, emphasizing that even the essential force for action is absent or ineffective. The entire phrase thus paints a picture of a reservoir of capability that is entirely depleted, moving from a lack of skill, to a failure of action, and ending in an absence of the fundamental power required for any effort.