Hog swimming in some pool (10)
I believe the answer is:
monopolise
'hog' is the definition.
('hog'->'monopolize' is in my internal thesaurus and 'ize'->'ise')
'swimming in some pool' is the wordplay.
'swimming' indicates an anagram (letters swim around into a new order).
'in'+'some'+'pool'='insomepool'
'insomepool' anagrammed gives 'MONOPOLISE'.
(Other definitions for monopolise that I've seen before include "Demand full attention" , "Control exclusively" .)