se·ren·i·ty

[suh-ren-i-tee]

–noun  , plural -ties for 2. 

1. the state or quality of being serene, calm, or tranquil; sereneness. 

2. ( usually initial capital letter ) a title of honor, respect, or reverence, used in speaking of or to certain members of royalty (usually preceded by his, your,  etc.). 

 —Synonyms
1.  composure, calm, peacefulness, peace.

—Antonyms
1.  agitation.