busk vs lifeboat

busk

verb
  • To tack, cruise about. 

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

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

  • A corset. 

lifeboat

verb
  • To rescue; to carry to safety 

noun
  • A boat especially designed for saving the lives of shipwrecked people or people in distress at sea (either launched from the shore with a crew, or else carried on board a larger ship). 

  • An emergency vehicle carried aboard a spaceship. 

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