Overrode protestor about concealing weapon (7)
I believe the answer is:
torpedo
'weapon' is the definition.
(weapon used at sea)
'overrode protestor about concealing' is the wordplay.
'concealing' says the answer is hidden in the clue.
'about' says the letters should be written backwards.
'odeprot' is hidden in the letters of 'overrode protestor'.
'odeprot' reversed gives 'TORPEDO'.
(Other definitions for torpedo that I've seen before include "(Of a project) cause to sink without trace" , "fish you want" , "Anti-ship weapon" , "Destroy" , "Underwater bomb" .)