See serenity in Webster's New World Roget's A-Z Thesaurus II
noun
Lack of emotional agitation:
calm, calmness, peace, peacefulness, placidity, placidness, quietude, tranquillity. See calmAn absence of motion or disturbance:
calm, calmness, hush, lull, peace, peacefulness, placidity, placidness, quiet, quietness, stillness, tranquillity, untroubledness. See calm
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