boon vs lifeguard

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. 

lifeguard

noun
  • A lifesaver. 

  • An attendant, usually an expert swimmer, employed to save swimmers in trouble or near drowning at a body of water. 

  • A sturdy metal bracket fixed in front of each of the leading wheels of a train to deflect small objects away from the wheels to prevent derailment. 

  • A bodyguard or unit of bodyguards, a guard of someone's (especially a king's) life or person. 

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