irritation in WordNet English dictionary

1. unfriendly behavior that causes anger or resentment
   aggravation  irritation  provocation 
   
2. the act of troubling or annoying someone
   annoyance  annoying  irritation  vexation 
   
3. the psychological state of being irritated or annoyed
   irritation  annoyance  vexation  botheration 
   
4. an uncomfortable feeling of mental painfulness or distress
   discomfort  soreness  irritation 
   
5. the neural or electrical arousal of an organ or muscle or gland
   excitation  innervation  irritation 
   
6. a sudden outburst of anger
   "his temper sparked like damp firewood"
   pique  temper  irritation 
   
7. (pathology) abnormal sensitivity to stimulation
   "any food produced irritation of the stomach"
   irritation