A depreciative, meaning weakly moral and religious. In French, bon homme is used in a similar way.
“No doubt, if a Caesar or a Napoleon comes before some man of weak will ... especially if he be a goody man, [he] will quail.” —J. Cook: Conscience, lecture iv. p. 49.
is good-wife, Chaucer's good-lefe; as, Goody Dobson. Good-woman means the mistress of the house, contracted sometimes into gommer, as goodman is into gomman. (See Goodman.)
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Goody from Fact Monster: