noun
1. the act of troubling or annoying someone
Synonym: annoyanceannoyingvexation
2. unfriendly behavior that causes anger or resentment
Synonym: aggravationprovocation
3. an uncomfortable feeling of mental painfulness or distress
Synonym: discomfortsoreness
4. a sudden outburst of anger
e.g. his temper sparked like damp firewood
Synonym: piquetemper
5. the neural or electrical arousal of an organ or muscle or gland
Synonym: excitationinnervation
6. the psychological state of being irritated or annoyed
Synonym: annoyancevexationbotheration
7. (pathology) abnormal sensitivity to stimulation
e.g. any food produced irritation of the stomach