"peacefulness" in the noun sense
1. peaceableness, peacefulness
a state that is calm and tranquil
2. peace, peacefulness, peace of mind, repose, serenity, heartsease, ataraxis
the absence of mental stress or anxiety
Source: WordNet® (An amazing lexical database of English)
Princeton University "About WordNet®."
WordNet®. Princeton University. 2010.
View WordNet® License