Polish Romeo getting black eye (6)
I believe the answer is:
shiner
'black eye' is the definition.
(synonyms)
'polish romeo' is the wordplay.
'polish' becomes 'shine' (synonyms).
'romeo' becomes 'r' (phonetic alphabet: alpha, bravo, charlie etc.).
'shine'+'r'='SHINER'
'getting' is the link.
(Other definitions for shiner that I've seen before include "Light" , "What one might get from boxer" , "A slangy black eye" , "Black eye (colloq.)" , "Informally, a black eye" .)