Manly versus Illawarra starts to annoy (6)
I believe the answer is:
virile
'manly' is the definition.
(I know that manly can be written as virile)
'versus illawarra starts to annoy' is the wordplay.
'starts to' suggests taking the first letters.
'annoy' becomes 'rile' (synonyms).
The initial letters of 'versus illawarra' is 'vi'.
'vi'+'rile'='VIRILE'
(Other definitions for virile that I've seen before include "Potent" , "Masculine and macho" , "Vigorous, manly" , "Robustly masculine" , "male" .)