infirmity vs malady

infirmity

noun
  • a moral weakness or defect 

  • feebleness, frailty or ailment, especially due to old age. 

malady

noun
  • A moral or mental defect or disorder. 

  • Any ailment or disease of the body; especially, a lingering or deep-seated disorder. 

How often have the words infirmity and malady occurred in a corpus of books? (source: Google Ngram Viewer )