1. A person who sleeps deeply and is difficult to wake up; someone whose sleep is profound and undisturbed by noise or movement
My father is a heavy sleeper; nothing can wake him up in the morning.
Meu pai tem sono pesado; nada consegue acordá-lo de manhã.
2. Characteristic of deep, sound sleep that is not easily interrupted
She has heavy sleep and doesn't hear the alarm clock.
Ela tem sono pesado e não ouve o despertador.