Shout of approval from supporter - "Five-nil!" (5)
I believe the answer is:
'shout of approval' is the definition.
(I've seen this before)
'supporter five-nil' is the wordplay.
'supporter' becomes 'bra' (I've seen this before).
'five' becomes 'v' (roman numeral).
'nil' becomes 'o'.
'from' acts as a link.
(Other definitions for bravo that I've seen before include "Hurrah!" , "A cry meaning well done" , "Good job!: international radio code word" , ""Well done, old chap!"" , "Exclamation of approval" .)