Antonyms for the phrase "being engrossed in" could include phrases such as "being distracted from," "being disinterested in," or "not paying attention to." Whereas being engrossed implies a strong focus and interest in something, being distracted from indicates a lack of focus or attention. Similarly, being disinterested in something means that you simply have no interest in that particular activity or subject matter, whereas being engrossed would imply a strong emotional attachment. Finally, not paying attention to something could be the opposite of being engrossed in something, indicating a lack of interest or attention overall.