The term "calmative" refers to something that has a soothing or calming effect. Antonyms for calmative include "stimulant," "irritant," or "aggravating." Stimulants are substances or actions that increase energy and excitement, often leading to restlessness or agitation, such as caffeine or loud music. Irritants are substances or actions that cause discomfort, such as itchiness, burning, or pain, like poison ivy or loud, bothersome noise. Lastly, aggravating pertains to anything that increases frustration or irritation, like a long wait time or a difficult problem. Opposites of calmatives can be beneficial in certain situations or activities, but may cause negative effects if overused.