Crossword Genius

Obsessive person in teachers’ union (3)

Ross

I believe the answer is:

nut

I believe this clue is a quadruple definition!!

'obsessive' is the first definition.
(I've seen this before)

'person' is the second definition.
(nut is a kind of person)

'in' acts as a link.

'teachers'' is the third definition.
(National Union of Teachers)

'union' is the fourth definition.
(National Union of Teachers)

(Other definitions for nut that I've seen before include "something turned when making fast > food" , "eg Almond, brazil" , "Hard shell of a locking device" , "Screwball" , "Fan" .)

I've seen this clue in The Times.
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