Brain fags, also known as mental exhaustion or burnout, can have a significant impact on a person's mental health and wellbeing. However, there are several antonyms or opposite terms that can be used to describe a clear and focused mind. These include mental freshness, mental rejuvenation, mental clarity, mental energy, mental alertness, and mental sharpness. These antonyms imply a sense of calmness, productivity, and efficiency, that is absent in the state of brain fags. To achieve mental freshness and clarity, one should take breaks, engage in relaxing activities, adopt a healthy lifestyle and take care of their mental health through meditation, therapy, or seeking support from loved ones.