perspiration vs sudation

perspiration

noun

  • The action or process of perspiring. 

  • Hard work. 

  • A saline fluid secreted by the sweat glands; sweat. 

sudation

noun

  • The process of perspiring. 

  • Perspiration; sweat (fluid). 

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