City in retreat — Coventry wingers showing good form (7)

I believe the answer is:

decency

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'good form' is the definition.

'city in retreat coventry wingers' is the wordplay.
'city' becomes 'ec' (the City of London postcode).
'in' means one lot of letters goes inside another.
'retreat' becomes 'den'.
'coventry wingers' becomes 'cy' (I can't explain this - if you can you should believe this answer much more).
'ec' placed inside 'den' is 'decen'.
'decen'+'cy'='DECENCY'

'showing' acts as a link.

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(Other definitions for decency that I've seen before include "Decorum" , "Goodness - sense of what is fitting" , "proper behaviour" , "Acceptable behaviour" , "Good taste; integrity" .)

I've seen this clue in The Guardian.

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