Great, brilliant, bang-on. Good job!

Varietyspeak for outstanding; usually referring to box office performance.

Boffo can also refer to:
A dollar (usually in the plural, Boffos).
A laugh, although boffola is more common.
Among criminals, boffo can mean a year, especially a jail sentence lasting a one year.

It is speculated that boffo is a corruption of box office.