Monomania suggests an unhealthy, excessive interest beyond normal hobby levels. His monomania with trains made him neglect his social life.
Pro Tip 2/3
Not Clinical
Used in everyday language, not necessarily referring to a medical condition. She exhibited a monomania for perfect grades.
Pro Tip 3/3
Potential Disapproval
Monomania often implies others might view the behavior as odd or excessive. People were put off by his monomania for documenting every detail of his life.