The idiom **岌岌可危** is formed through a vivid descriptive structure: the reduplicated adjective **岌岌** (jíjí), which originally depicts the towering and perilous appearance of a high mountain, is combined with the phrase **可危** (kě wēi), meaning "can be dangerous." Together, they create a powerful metaphor where the repeated "岌岌" intensifies the sense of imminent collapse, as if something is as precariously poised as a towering peak about to topple, thereby graphically conveying a state of extreme danger and instability.