A couple of guys initially facing resistance over making trouble (5)
I believe the answer is:
aggro
'trouble' is the definition.
(short for aggression or aggravation)
'a couple of guys initially facing resistance over' is the wordplay.
'couple of' shows that letters should be duplicated.
'initially' suggests taking the first letters.
'facing' is a charade indicator (letters next to each other).
'resistance' becomes 'r' (electronics abbreviation).
'over' becomes 'o' (cricket abbreviation).
The initial letter of 'guys' is 'g'.
'g' duplicated is 'gg'.
'a'+'gg'+'r'+'o'='AGGRO'
'making' is the link.
(Other definitions for aggro that I've seen before include "Grief" , "Greek consumed by past" , "Boorish, threatening behaviour (slang)" , "Slang for deliberate trouble-making" , "Potential violence" .)