boon vs setback

boon

noun
  • The woody portion of flax, separated from the fiber as refuse matter by retting, braking, and scutching. 

  • A good thing; a blessing or benefit; a thing to be thankful for. 

  • An unpaid service due by a tenant to his lord. 

adj
  • gay; merry; jovial; convivial. 

setback

noun
  • An offset to the temperature setting of a thermostat to cover a period when more or less heating is required than usual. 

  • An obstacle, delay, disadvantage, blow (an adverse event which retards or prevents progress towards a desired outcome) 

  • A step-like recession in a wall. 

  • The required distance between a structure and a road. 

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