The word "more riveted" implies a certain level of fixation or absorption. Antonyms for this phrase could include "disinterested," "unconcerned," or "apathetic," which suggest a lack of interest or engagement with a topic or activity. Other antonyms might include "inattentive," "distracted," or "bored," which suggest a lack of focus or engagement with one's surroundings. These words can be useful for finding a way to describe someone who is not captivated by a particular topic, or who may be struggling to pay attention due to other distractions or concerns. Overall, the opposite of "more riveted" would be any term suggesting disinterest, distraction, or lack of focus.