Sole perhaps caught in drain (6)
I believe the answer is:
finish
'drain' is the definition.
(thesaurus)
'sole perhaps caught in' is the wordplay.
'sole perhaps' becomes 'fish' (sole is a kind of fish).
'caught' is an insertion indicator.
'fish' placed around 'in' is 'FINISH'.
(Other definitions for finish that I've seen before include "'End, close (6)'" , "Cease, conclude" , "Refinement in social graces" , "Bring to an close" , "Deal with" .)