Phobia
An unreasonable sort of fear that can cause avoidance and panic.
Phobias are a relatively common type of anxiety disorder.
For example, extreme fear of spiders is called arachnophobia, and fear of being outside is known as agoraphobia.
Phobias can be treated with cognitive behavioral therapy using exposure and fear reduction techniques.
In many cases, anti-anxiety or anti-depressant medication proves helpful, especially during the early stages of therapy.
The word 'phobia' is from the Greek 'phobos' (fear).