Swimmer wildly exaggerated finale of race on river (5)

I believe the answer is:

otter

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'swimmer' is the definition.
(animal which swims)

'exaggerated finale of race on river' is the wordplay.
'exaggerated' becomes 'OTT' (short for 'over the top').
'finale of' indicates one should take the final letters.
'on' is a charade indicator (letters next to each other).
'river' becomes 'r' (abbreviation for river).
The last letter of 'race' is 'e'.
'ott'+'e'+'r'='OTTER'

'wildly' acts as a link.
I am not very happy about this link. It may be part of another bit of the clue.

Can you help me to learn more?

(Other definitions for otter that I've seen before include "Holt dweller" , "Tarka, for one" , "Water mammal" , "furry creature" , "Torte (anag)" .)

I've seen this clue in The Independent.

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