Added 9 October 2026 peacefulness noun Categories: Describing WordsFeelingsRare Words noun ! Definition from WordNet 3.1, Princeton University. More about peacefulness at Wordnik → Where our words come from → A state that is calm and tranquil. The absence of mental stress or anxiety. Related Words: peaceablenessserenitypeaceataraxisreposeheartseasepaixpeaceabilityplaciditytranquillitytranquilness Back to today's word