Calmness, n.
The state of quality of being calm; quietness; tranquillity; self-repose. The gentle calmness of the flood. Denham. Hes calmness was the repose of conscious power. E. Everett.
Syn. -- Quietness; quietude; stillness; tranquillity; serenity; repose; composure; sedateness; placidity.
Shades of meaning
Fernald has no entry of its own for calmness; he lists it under apathy, patience, rest.
Where he writes about it:
While apathy is want of feeling, calmness is feeling without agitation. — from apathy
Calmness is the result of strength, courage, or trust; apathy is the result of dulness or weakness. — from apathy
Synonyms
apathypatiencerestcalmcessationcomposureeaseenduranceforbearancefortitudeimmobilityimpassibilityindifferenceinsensibilityintermissionleniencylethargylong-sufferingpausepeacepeacefulnessphlegmquiescencequietquietnessquietuderecreationreposeresignationsleepsluggishnessslumberstaystillnessstoicismstopsubmissionsufferancetranquillityunconcernunfeelingness