knocker vs negativist

knocker

noun
  • A critic; one who disparages. 

  • A person who knocks. 

  • A person who knocks (denigrates) something. 

  • One who defaults on payment of a wager. 

  • A woman's breast. 

  • A large cockroach, especially Blaberus giganteus, of semitropical America, which is able to produce a loud knocking sound. 

  • A large, boulder-shaped outcrop of bedrock in an otherwise low-lying landscape, chiefly associated with a mélange. 

  • A device, usually hinged with a striking plate, used for knocking on a door. 

  • A mechanical device in a pinball table that produces a loud percussive noise. 

negativist

noun
  • One who exhibits negativism. 

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