A phobia is an overwhelming and debilitating fear of an object, place, situation, feeling or animal.
Phobias are more pronounced than fears. They develop when a person has an exaggerated or unrealistic sense of danger about a situation or object.
If a phobia becomes very severe, a person may organise their life around avoiding the thing that's causing them anxiety. As well as restricting their day-to-day life, it can also cause a lot of distress.
Phobias are often laughed off by other people, but in reality they can control a persons life, no matter how trivial it may appear to others.