Scrum half came over the protected side (5)
I believe the answer is:
melee
'scrum' is the definition.
(I've seen this in another clue)
'half came over the protected side' is the wordplay.
'half' suggests halving the letters.
'over' is a charade indicator (letters next to each other) (in a down clue, some letters go over others).
'the protected side' becomes 'lee' (I've seen this in another clue).
'came' cut in half is 'me'.
'me'+'lee'='MELEE'
(Other definitions for melee that I've seen before include "Fracas" , "Scrap" , "Affray; muddled group" , "A confused free-for-all" , "Confused conflict, affray" .)