One of the
characteristics of living things, it is defined as the ability of an
organism to respond to external
stimuli like
touch,
heat,
light,
electricity, etc. Every living thing is
irritable (some more so than others, especially during
menopause - sorry mom, I had to say it!). Many simpler organisms like
plants respond to stimuli by moving towards or away from the stimulus. Movement towards the
stimulus is called a
positive response, and movement away from it is called
negative response.
So if someone calls you an irritable bitch, tell them that you're proud of it because it's what makes you alive.