The Rice University Neologisms Database

A person who obsesses over being completely organized and orderly. A "neat freak" is a person who is free of any kind of disorder or clutter. This type of person usually has a very systematic way of arranging things so that they stay in order. A person that is this engrossed in keeping things in order may be thought of as having a behavior that is a little extreme, which could seem abnormal causing them to be called a type of "freak".