legging vs underclothing

legging

noun
  • A covering, usually of leather, worn from knee to ankle. 

  • The process of putting a series of three or more options strikes into the stock market. 

  • One of the legs of a pair of trousers. 

  • Tight fitting leg coverings worn, for example, to gym. 

underclothing

noun
  • clothing worn next to the skin; underwear 

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