Swollen duke first to have finished (9)

I believe the answer is:

distended

'swollen' is the definition.
(synonyms)

'duke first to have finished' is the wordplay.
'duke' becomes 'd' (abbreviation).
'first to' becomes 'ist' (I've seen this in other clues).
'have' is a charade indicator (letters next to each other).
'finished' becomes 'ended' ('end' can be a synonym of 'finish').
'd'+'ist'+'ended'='DISTENDED'

(Another definition for distended that I've seen is " Swollen with pressure".)

I've seen this clue in The Daily Express.

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