Shout to arrest men going berserk in scrap (7)
I believe the answer is:
remnant
'scrap' is the definition.
(synonyms)
'shout to arrest men going berserk' is the wordplay.
'shout' becomes 'rant' (I've seen this in other clues).
'to arrest' is an insertion indicator.
'going berserk' is an anagram indicator.
'men' anagrammed gives 'emn'.
'rant' going around 'emn' is 'REMNANT'.
'in' is the link.
(Other definitions for remnant that I've seen before include "Rent-man (anag.)" , "Leftover piece of cloth" , "Surviving fragment" , "faithful minority" , "Men rant poorly when it's left over" .)