Agitative means something that is causing or tending to cause agitation, excitement or disturbance. And some of the antonyms for this word are calm, peaceful, tranquil, serene, composed, relaxed, settled, still, stable, quiet, and steady. These words are the exact opposite of agitative, as they describe a state of mind or a situation that is free from any kind of disturbance, commotion or upheaval. For example, a calm sea, a peaceful mind, a tranquil environment, a serene landscape, a composed attitude, a relaxed body, a settled dispute, a still night, a stable condition, a quiet neighborhood, and a steady job. So, whenever you feel agitated or disturbed, try to create a peaceful, calm and serene environment around you.