Nouns

(n)centrist, middle of the roader, moderate, moderationista person who takes a position in the political center

Verbs

(v)moderate, chair, leadpreside over“John moderated the discussion”
(v)moderatemake less fast or intense“moderate your speed”
(v)control, hold in, hold, contain, check, curb, moderatelessen the intensity of; temper; hold in restraint; hold or keep within limits“moderate your alcohol intake”, “hold your tongue”, “hold your temper”, “control your anger”
(v)mince, soften, moderatemake less severe or harsh“He moderated his tone when the students burst out in tears”
(v)tone down, moderate, tamemake less strong or intense; soften“Tone down that aggressive letter”, “The author finally tamed some of his potentially offensive statements”
(v)temper, season, mollify, moderatemake more temperate, acceptable, or suitable by adding something else“she tempered her criticism”

Adjectives

(a)moderatebeing within reasonable or average limits; not excessive or extreme“moderate prices”, “a moderate income”, “a moderate fine”, “moderate demands”, “a moderate estimate”, “a moderate eater”, “moderate success”, “a kitchen of moderate size”, “the X-ray showed moderate enlargement of the heart”
(s)moderate, temperatenot extreme“a moderate penalty”, “temperate in his response to criticism”
(s)moderate, restrainedmarked by avoidance of extravagance or extremes“moderate in his demands”, “restrained in his response”