Sluggish swim with rubbish around (6)
I believe the answer is:
torpid
'sluggish' is the definition.
(I've seen this before)
'swim with rubbish around' is the wordplay.
'swim' becomes 'dip' (dip is a kind of swim).
'with' means one lot of letters go next to another.
'rubbish' becomes 'rot' (I've seen this before).
'around' says the letters should be written backwards.
'dip'+'rot'='diprot'
'diprot' back-to-front is 'TORPID'.
(Other definitions for torpid that I've seen before include "Sluggish and inactive" , "Conservative nearly given money to withhold article" , "Slow, dull" , "Slow and apathetic" , "hibernating?" .)