To moderate. 1. To restrain from excess of any kind; to reduce from a state of violence, intensity, or excess; to keep within bounds; to make temperate; to lessen; to allay; to repress; to temper; to qualify; as, to moderate rage, action, desires, etc.; to moderate heat or wind. 2. To become less violent, severe, rigorous, or intense; as, the wind has moderated.