noun
1. a feeling of calmness; a quiet and undisturbed feeling
• Syn: ↑placidness
• Derivationally related forms: ↑placid (for: ↑placidness)
• Hypernyms: ↑calmness
2. a disposition free from stress or emotion
• Syn: ↑repose, ↑quiet, ↑serenity, ↑tranquillity, ↑tranquility
• Hypernyms: ↑composure, ↑calm, ↑calmness, ↑equanimity
• Hyponyms: ↑ataraxia
Useful english dictionary. 2012.