adjective: serene; comparative adjective: serener; superlative adjective: serenest
calm, peaceful, and untroubled; tranquil.
"her eyes were closed and she looked very serene"
an expanse of clear sky or calm sea.
"not a cloud obscured the deep serene"
synonyms: cloudless, unclouded, clear, bright, sunny
"the serene western sky"
antonyms: cloudy, stormy