The antonyms for the word "fired-up" are calm, relaxed, subdued, and sluggish. When someone is not fired-up, they may appear to be disinterested, apathetic or indifferent. They might also lack energy, enthusiasm, or motivation. Being calm indicates a state of being composed, tranquil, and peaceful, which reflects a sense of control and maturity. On the other hand, being relaxed shows a sense of ease, comfort, and serenity, which is opposite to the excitement and intensity of being fired-up. Subdued means to be restrained, meek or quiet, contrasting the energy and impulsiveness of being fired-up. Lastly, sluggish means slow-moving or lethargic, which is contrary to the dynamic and fast-paced nature of being fired-up.