moderate

As an adjective, "moderate" describes something that is not extreme, or is average and within reasonable limits (e.g., "moderate risk," "moderate speed"). As a transitive verb, "moderate" means to make something less intense or extreme, or to chair a discussion (e.g., "moderate expectations," "moderate a debate"). As an intransitive verb, it means to become less intense or extreme (e.g., "the storm moderated"). As a noun, "a moderate" refers to a person whose political or ideological views are not extreme.