1. A person who sleeps soundly, deeply, and without disturbance or worry
He is someone who has peaceful sleep and wakes up refreshed.
Ele é alguém que tem sono tranquilo e acorda refreshed.
2. Someone with a clear conscience who is not troubled by guilt or anxiety
She sleeps peacefully because she has nothing to feel guilty about.
Ela tem sono tranquilo porque não tem nada pelo que se sentir culpada.