noun
A psychiatric term for an excessive, obsessive preoccupation with a single idea or subject. In everyday Japanese, it can also refer to an extreme fixation or obsession, similar to 'monomania' in English.
彼のモノマニア的な収集癖には驚かされる。
His monomaniacal collecting habit is astonishing.
その作家は特定のテーマにモノマニア的なこだわりを持っている。
That writer has a monomaniacal fixation on a particular theme.