With that the working week comes to a close, chum! (6)
I believe the answer is:
friend
'chum' is the definition.
(I've seen this in another clue)
'with that the working week comes to a close' is the wordplay.
I cannot quite understand how this works, but
'close' could be 'end' (close can mean to end or finish) and 'end' is present in the answer.
The remaining letters 'fri' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for friend that I've seen before include "Person regarded with trust and affection" , "one quaking in society?" , "Pal, mate" , "Person with whom you have a bond of mutual affection" , "Close associate" .)