Sentence:  And like bright metal on a sullen ground, / My <WSD>reformation</WSD>, glittering o'er my fault, / Shall show more goodly, and attract more eyes / Than that which hath no foil to set it off. 
Meaning of the word marked with <WSD> tags:  An improvement (or an intended improvement) in the existing form or condition of institutions or practices, etc.; intended to make a striking change for the better in social, political or religious affairs or in the conduct of persons or operation of organizations.