He charges a couple of hundred to the employer (7)
I believe the answer is:
accuser
'he charges' is the definition.
(I've seen this before)
'a couple of hundred to the employer' is the wordplay.
'couple of hundred' becomes 'CC' (Roman numerals for 200).
'to the employer' becomes 'user' (someone who employs or uses something).
'a'+'cc'+'user'='ACCUSER'
(Other definitions for accuser that I've seen before include "Person making a charge" , "One bringing charges" , "Person charging" , "One who blames" , "One charging" .)