downside vs weakness

downside

noun
  • A disadvantageous aspect of something that is normally advantageous. 

  • A downward tendency, especially in the price of shares etc. 

  • The side of something that is at the bottom, or that is intended to face downward. 

weakness

noun
  • The condition of being weak. 

  • An inadequate quality; fault 

  • A special fondness or desire. 

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