Fancy orthopaedic back cushions (4)

I believe the answer is:

idea

I'm a little stuck... Click here to teach me more about this clue!

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

I can't explain the remainder of the clue.

(Other definitions for idea that I've seen before include "Notion, belief" , "Inkling" , "Thought, belief" , "Theory" , "Product of the mind" .)

I've seen this clue in The Telegraph.

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