According to Fowler, it actually
denotes a "group of repressed emotional ideas responsible for an abnormal
mental condition," but it has evolved into a synonym for "a bee in one's
bonnet"; what word is it?
Etymology, Etymology, and more Etymology
as well as grammar, usage, euphemism, slang, jargon, semantics, linguistics, neologism, idiom, cant, and argot.

The critically-acclaimed board game
MooT
consists of tough questions about the nuances of the English language.
Answer:
complex
Source: Fowler's Modern English Usage
(1919)
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