incredulity vs suspicion

incredulity

noun
  • Unwillingness or inability to believe; doubt about the truth or verisimilitude of something; disbelief. 

  • Religious disbelief, lack of faith. 

suspicion

noun
  • The imagining of something without evidence. 

  • Uncertainty, doubt. 

  • The act of suspecting something or someone, especially of something wrong. 

  • A trace, or slight indication. 

  • The condition of being suspected. 

verb
  • To suspect; to have suspicions. 

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