irritation

Short definition from Wiktionary

Noun

1. 1
   The act of irritating or annoying.
2. 2
   The state of being irritated.
3. 3
   A thing or person that annoys.
4. 4
   A state of inflammation or of painful reaction to cell or tissue damage.
5. 5
   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.