There are numerous synonyms for the phrase "paying attention." One of the most commonly used synonyms is "being attentive," which means showing interest and focus towards what is happening. Another synonym is "being mindful," which means being aware of one's surroundings and fully engaged in the present moment. "Concentrating" is also a popular synonym, which means focusing one's attention on a particular task or situation. Other synonyms for paying attention include "listening carefully," "keeping watch," and "observing closely." No matter which synonym is used, the key is to ensure that one is fully engaged and focused on the task or situation at hand.