Calm, Tranquil
noun, な adjective, の adjective
A flat calm is a calm and tranquil place.
へいおん
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
俺は平穏無事に暮らすことが嫌いだ。
I don’t like living in peace and quiet.