Romeo finished as a pirate! (5)
I believe the answer is:
rover
'a pirate' is the definition.
(thesaurus)
'romeo finished' is the wordplay.
'romeo' becomes 'r' (phonetic alphabet: alpha, bravo, charlie etc.).
'finished' becomes 'over' ('over' can be similar in meaning to 'finished').
'r'+'over'='ROVER'
'as' acts as a link.
(Other definitions for rover that I've seen before include "Pirate; dog's name" , "Car - dog" , "Person given to wandering" , "one in Bristol, one in Doncaster, perhaps" , "Itinerant person" .)