The word "不寒而栗" is formed by sequentially combining the characters 不 (not), 寒 (cold), 而 (but), and 栗 (tremble), resulting in a literal meaning of "not cold but trembling". The structure negates the state of being cold with 不, links it to the action of trembling via the conjunction 而, and creates a direct contrast that metaphorically conveys experiencing fear or dread without physical cold.