irritation

noun

• 1the state of feeling annoyed, impatient, or slightly angry:much to my irritation, Chris fell asleep
• [count noun] a thing that annoys or irritates someone:the minor irritations of life

• 2inflammation or other discomfort in a body part caused by reaction to an irritant substance: some chemicals cause a direct irritation to the skin leading to dermatitis
• Biology the stimulation of an organism, cell, or organ to produce an active response.