irritate vs torment

irritate

verb
  • To induce pain in (all or part of a body or organism). 

  • To cause or induce displeasure or irritation. 

  • To provoke impatience, anger, or displeasure in. 

torment

verb
  • To cause severe suffering to (stronger than to vex but weaker than to torture.) 

noun
  • Any extreme pain, anguish or misery, either physical or mental. 

  • Torture, originally as inflicted by an instrument of torture. 

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