excitation vs irritation

excitation

noun
  • The act of exciting or putting in motion; the act of rousing up or awakening. 

  • The activity produced in an organ, tissue, or part, such as a nerve cell, as a result of stimulation 

  • The act of producing excitement (stimulation); also, the excitement produced. 

  • A transition of a nucleus, atom or molecule to an excited state by the absorption of a quantum of energy; the opposite of relaxation 

irritation

noun
  • The act of irritating or annoying 

  • A things or person that annoys 

  • A condition of morbid excitability or oversensitiveness of an organ or part of the body; a state in which the application of ordinary stimuli produces pain or excessive or vitiated action. 

  • The state of being irritated 

  • a state of inflammation or painful reaction to allergy or cell-lining damage. 

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