Fruitlessly refusing to take tiller - they're so pernickety (5)

I believe the answer is:

fussy

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'pernickety' is the definition.
(synonyms)

I cannot understand how the rest of the clue works.

(Other definitions for fussy that I've seen before include "Hard to please" , "Pernickety" , "Overprecise" , "Overly particular" , "Finicky, picky" .)

I've seen this clue in The Irish Times.

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