The word "EXER" doesn't exist in the English language, so there cannot be any antonyms for it. However, if we were to consider a similar word such as "exercise," antonyms could be laziness, inactivity or idleness. Exercise suggests movement, activity and exertion, so its antonyms reflect the opposite - a lack of movement, a sedentary lifestyle or avoiding physical activity. It is important to maintain an active lifestyle to promote physical and mental health, so finding the motivation to exercise regularly is crucial. While it can be challenging to get started, the benefits of regular exercise are undeniable.