Calmatives are substances or medications that have a sedative effect on a person's mind or body. On the other hand, antonyms for calmatives are stimulants, excitants, or energizers. These types of substances or medications have the opposite effect of calmatives, as they increase alertness, energy, and arousal. Stimulants are often used to combat fatigue, increase mental alertness, or promote weight loss. In contrast, calmatives are used to reduce anxiety, promote relaxation, or induce sleep. While both calmatives and stimulants have their uses, it's important to use them responsibly and under the guidance of a medical professional.