The word "盯住" is formed by combining the character "盯", meaning to stare, which consists of the radical "目" (eye) indicating its relation to vision and the component "丁" suggesting its pronunciation, with the character "住", meaning to stay or remain, which consists of the radical "亻" (person) and the component "主" contributing to its sound and meaning; together, "住" modifies "盯" to imply a continuous or fixed action, resulting in the meaning of staring steadily or keeping an eye on something.