Unreal being fine and insubstantial (5)

I believe the answer is:

fairy

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'unreal being' is the definition.
'fairy' can be an answer for 'being' (fairy is a kind of being). I'm not certain of the 'unreal' bit.

'fine and insubstantial' is the wordplay.
'fine' becomes 'f' (abbreviation).
'and' says to put letters next to each other.
'insubstantial' becomes 'airy' (similar in meaning).
'f'+'airy'='FAIRY'

Can you help me to learn more?

(Other definitions for fairy that I've seen before include "Mythical being" , "Tinker Bell was one" , "Cobweb, perhaps" , "- Cake, - godmother" , "Eg, Tinkerbell" .)

I've seen this clue in The Guardian.

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