1. to produce a sound that lacks depth, resonance, or substance; to appear insincere or unconvincing when spoken
His apology sounded hollow because he didn't seem genuinely remorseful.
Seu pedido de desculpas soou oco porque ele não parecia genuinamente arrependido.
2. to emit a sound characteristic of empty space or lack of substance
The knock on the wooden door sounded hollow.
A batida na porta de madeira soou oca.