Translation guide
A person obsessed with a single idea or subject. In Japanese, this is expressed through nouns describing obsession, or by describing someone as fixated on one thing.
Describing someone who is fixated on a single topic or idea, often to an extreme degree.
A direct translation meaning 'monomaniac' or someone with a monomania. It's a clinical/psychological term, but can be used in everyday language to describe someone obsessively fixated.
He's a monomaniac about work.
Literally 'single-minded person'. It has a more positive nuance than 'monomaniac', implying dedication rather than pathology. Use when the obsession is seen as admirable.
He's single-mindedly devoted to his research.
Means 'a person possessed by one thing'. It conveys the obsessive, almost supernatural fixation of a monomaniac.
Loanword from English 'mania', used for enthusiasts or fanatics. It can imply a monomaniacal focus, but is often lighter, like 'otaku'. Use with caution as it may not carry the pathological weight.
Directly translating 'monomaniac' as モノマニアック is not natural Japanese. Use the provided options instead.
He is a monomaniac. (unnatural)
He's like a man possessed by a single idea.
He's a train maniac.