clamor vs knock on wood

clamor

verb
  • To influence by outcry. 

  • To cry out and/or demand. 

  • To demand by outcry. 

  • To become noisy insistently. 

noun
  • Any loud and continued noise. 

  • A continued public expression, often of dissatisfaction or discontent; a popular outcry. 

  • A great outcry or vociferation; loud and continued shouting or exclamation. 

knock on wood

verb
  • To take a customary action to ward off some misfortune that is believed to be attracted by a presumptuous statement. 

intj
  • Hopefully; a self-directive to undertake the customary action to ward off bad luck. 

How often have the words clamor and knock on wood occurred in a corpus of books? (source: Google Ngram Viewer )