boon vs sweetener

boon

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

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

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

adj
  • gay; merry; jovial; convivial. 

sweetener

noun
  • Something given or added to added to a deal to sweeten another's attitude, especially a bribe or kickback. 

  • A shill bidder at an auction. 

  • Something added to food to sweeten its taste, especially an artificial substitute for sugar. 

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