instep vs trouser

instep

noun
  • A section of any footwear covering that part of the foot. 

  • In horses, the hind leg from the ham to the pastern joint. 

  • The arched part of the top of the foot between the toes and the ankle. 

trouser

noun
  • Of or relating to trousers. 

  • A pair of trousers. 

verb
  • To secretively steal (an item or money) for personal use. 

  • To put (money) into one's trouser pocket; to pocket. 

  • To take and keep (something, especially money, that is not one's own); to pocket. 

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