(St.). The patron saint who saves from infamy and reproach. This is from her fiery trial recorded in the tale of Susannah and the Elders.
This wife of Joiachim, being accused of adultery, was condemned to death by the Jewish elders; but Daniel proved her innocence, and turned the tables on her accusers, who were put to death instead. (The Apocrypha.)
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Susan from Fact Monster: