Same word as pacify:

allay, ameliorate, assuage, bury the hatchet, butter up, calm, chasten, compose, con, conciliate, cool, dulcify, fix up, grease, kiss and make up, lay back, lull, make peace, mitigate, moderate, mollify, pacificate, placate, propitiate, put the lid on, qualify, quell, quiet, relieve, repress, silence, smooth over, soft-pedal, soften, soothe, square, still, stroke, subdue, sweeten, take the edge off, tame, temper, tranquilize