One who can do you a deal of good or a deal of harm.
More Latin Proverbs:
The excess of mirth leads to tears.Latin
All power is impatient of a partner.
Latin
He who has plenty of pepper may season his food as he likes.
Latin
Sour grapes will ne'er make sweet wine.
Latin
Neglect will sooner kill an injury than revenge.
Latin
A contented mind is a continual feast.
Latin