0 a person who is extremely interested in only one thing, often to such a degree that they are mentally ill:
1 suffering from or relating to monomania (= a condition in which someone is extremely interested in one thing):
I'm not so much of a monomaniac as this collection makes me seem.
The single-minded ones, the monomaniacs, are the only true achievers.
You could either look at him as a man of total commitment or as a monomaniac.
The consequences of his judgmental, monomaniac vision are left for others to deal with.
You are drawn into his extravagant monomaniac vision.
