Well-paid woman having fun working (7)

I believe the answer is:

gainful

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'well' is the definition.
(thesaurus)

'paid woman having fun working' is the wordplay.
'paid woman' becomes 'gail' (I am not sure about the 'paid' bit.).
'having' indicates putting letters inside.
'working' indicates anagramming the letters.
'fun' with letters rearranged gives 'nfu'.
'gail' enclosing 'nfu' is 'GAINFUL'.

Can you help me to learn more?

(Other definitions for gainful that I've seen before include "Profitable and productive" , "Bringing in money" .)

I've seen this clue in The Daily Express.

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