Artist daydreaming first (14)

I believe the answer is:

abstractionist

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'first' is the definition.
Both the definition and answer are adjectives. Perhaps they are linked in a way I don't understand?

'artist daydreaming' is the wordplay.
'artist' becomes 'abstract artist' (abstract artist is a kind of artist).
'daydreaming' becomes 'ionist' (I can't justify this - if you can you should believe this answer much more).
'abstract'+'ionist'='ABSTRACTIONIST'

Can you help me to learn more?

I've seen this clue in The Daily Express.

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