One charging a junkie when carrying small amount (7)
I believe the answer is:
accuser
'one charging' is the definition.
(I've seen this before)
'a junkie when carrying small amount' is the wordplay.
'junkie' becomes 'user' (I've seen this before).
'when carrying' is an insertion indicator.
'small amount' becomes 'cc'.
'a'+'user'='auser'
'auser' going around 'cc' is 'ACCUSER'.
(Other definitions for accuser that I've seen before include "One who brings a charge" , "who tries to blame someone else" , "Plaintiff" , "One who brings charges" , "Person bringing charges" .)