Monopolise a wild animal (3)
I believe the answer is:
hog
This clue is a triple definition!
'monopolise' is the first definition.
(I've seen this before)
'a wild' is the second definition.
(thesaurus)
'animal' is the third definition.
(hog is a kind of animal)
(Other definitions for hog that I've seen before include "Domesticated pig" , "Greedy person or pig for slaughter" , "Domestic adult swine" , "Selfishly keep" , "Pig; hoard selfishly" .)