Energy level is a term used to describe a person's physical and mental vitality. It refers to how active, alert, and productive one is over a certain period of time. To describe this state, some synonyms for the term "energy level" include vigor, liveliness, animation, drive, verve, power, dynamism, enthusiasm, and zest. These words convey the sense of being full of vitality, spirit, and force. Additionally, synonyms like stamina, endurance, and resilience describe the ability to sustain energy levels over longer periods. In contrast, words like lethargy, listlessness, fatigue, and exhaustion indicate a lack of energy and a need for rest and rejuvenation.