Antonyms are opposing words with contrasting meanings. The opposite of re-energize is to weaken or drain energy, making someone feel exhausted or fatigued. Sapped, lethargic, depleted, and drained completely are some antonyms of re-energize. These words describe the feeling of being worn out both physically or mentally. Re-energize is the process of restoring energy, motivation, and vitality, whereas its antonyms depict a sense of lack and depletion. When feeling tired, it may be helpful to identify the specific cause of fatigue and take measures to combat it, such as getting adequate rest, exercise, or a healthy diet.