Mysophobia (from Greek μύσος - musos, "uncleanness" and φόβος - phobos, "fear"; also called germophobia/germaphobia, a combination of germ and phobia to mean "fear of germs", as well as bacillophobia, bacteriophobia, and spermophobia) is a pathological fear of contamination and germs. Someone who has such a fear is referred to as a mysophobe. The term was coined by Dr. William Alexander Hammond in 1879 when describing a case of obsessive-compulsive disorder (OCD) exhibited in repeatedly washing one's hands. Mysophobia has long been related to the OCD of constantly washing one's hands. However, Harry Stack Sullivan, an American psychologist and psychoanalyst, notes that while fear of dirt underlies the compulsion of a person with this kind of OCD, his or her mental state is not about germs; instead, this person feels the hands must be washed. Other names for abnormal persistent fear of dirt and filth include molysmophobia or molysomophobia, rhypophobia, and rupophobia
- This phobia is often mistaken with Mycophobia- the fear of Mushrooms and/or Fungi.