appeaser (n.)

c. 1300 appesen, "reconcile," from Anglo-French apeser, Old French apaisier "to pacify, make peace, appease, be reconciled, placate" (12c.), from the phrase a paisier "bring to peace," from a "to" (see ad-) + pais, from Latin pacem (nominative pax) "peace" (see peace). The meaning "pacify (one who is angry)" is from late 14c.; for political sense, see appeasement. Related: Appeased; appeasing.