Quietness(n.) The quality or state of being quiet; freedom from noise, agitation, disturbance, or excitement; stillness; tranquility; calmness.
Thesaurus Entries
accidia, acedia, aloofness, apathy, ataraxia, benumbedness, blah, blahs, bovinity, calmness, carelessness, casualness, comatoseness, composure, contemplation, coolness, detachment, disinterest, dispassion, dispassionateness, disregard, disregardfulness, dullness, easy temper, easygoingness, even temper, good temper, heartlessness, hebetude, heedlessness, hopelessness, impassiveness, impassivity, imperturbability, imperturbableness, inappetence, inattention, incuriosity, indifference, indiscrimination, inexcitability, inexcitableness, inirritability, insouciance, lack of affect, lack of appetite, lackadaisicalness, languidness, lethargicalness, lethargy, listlessness, lucid stillness, marmoreal repose, mindlessness, negligence, nirvana, nonchalance, numbness, passiveness, passivity, patience, peace, peacefulness, phlegm, phlegmaticalness, phlegmaticness, placidity, placidness, plucklessness, pococurantism, quiescence, quiescency, quiet, quietism, quietness, quietude, recklessness, regardlessness, repose, resignation, resignedness, rest, restfulness, sangfroid, satori, serenity, silence, silken repose, sleep, sloth, sluggishness, slumber, smooth temper, sopor, soporifousness, spiritlessness, spunklessness, steadiness, stillness, stoicism, stolidity, stupefaction, stupor, supineness, torpidity, torpidness, torpor, tranquillity, unanxiousness, unconcern, unirritableness, unmindfulness, unnervousness, unpassionateness, unsolicitousness, wise passiveness, withdrawnness