Swimmer staggers as if drunk when taking clothes off (5)
I believe the answer is:
otter
'swimmer' is the definition.
(animal which swims)
'staggers as if drunk when taking clothes off' is the wordplay.
'staggers as if drunk' becomes 'totters' (you might totter around when drunk).
'when taking clothes off' says to take the centre (letters which clothe the word are removed).
The middle of 'totters' is 'OTTER'.
(Other definitions for otter that I've seen before include "furry animal" , "eg Tarka" , "Tarka, for one" , "Playful aquatic animal of 'Tarka' fame" , "Water animal with webbed fee, brown fur and flat tail" .)