busk vs constrain

busk

verb
  • To solicit money by entertaining the public in the street or in public transport. 

  • To tack, cruise about. 

noun
  • A strip of metal, whalebone, wood, or other material, worn in the front of a corset to stiffen it. 

  • A corset. 

constrain

verb
  • To force physically, by strong persuasion or pressuring; to compel; to oblige. 

  • To keep within close bounds; to confine. 

  • To reduce a result in response to limited resources. 

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