"AM power" can be defined as the strength or ability to perform a task during the morning time. However, the opposite of this phrase can vary depending on the context in which it is used. If we are talking about someone's energy or strength during the evening, the antonym for "AM power" would be "PM power." In contrast, if we are referring to someone's lack of energy or weakness, the antonym would be "low energy" or "fatigue." Thus, the antonym for "AM power" differs based on the situation it is used in and depends on the opposite characteristic being referred to.