He might make end of ref or ref make end of him (8)
I believe the answer is:
offender
'him' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he might make end of ref or ref make end' is the wordplay.
'he might' becomes 'o' (I can't explain this - if you can you should give a lot more credence to this answer).
'make' is an anagram indicator.
'end of' says to take the final letters.
The last letters of 'ref or ref make' are 'frfe'.
'frfe'+'end'='frfeend'
'frfeend' with letters rearranged gives 'ffender'.
'o'+'ffender'='OFFENDER'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for offender that I've seen before include "Criminal" , "Transgressor, lawbreaker" , "miscreant" , "One breaking rule" , "Delinquent" .)