The term OPERA VILLAIN'S VOICE, OFTEN can be summarized by two crossword solutions: BASSO (5 letters) and BASS (4 letters). A BASSO is a type of male singing voice that is the lowest in range. It is often used for opera villains because of its deep and powerful sound. A BASS is also a type of male singing voice, but it is slightly higher in range than a BASSO. Both BASSO and BASS are commonly used in opera to create a dramatic effect.