Therefore finish up making a peace offering (3)
I believe the answer is:
sop
'a peace offering' is the definition.
(I've seen this in another clue)
'therefore finish up' is the wordplay.
'therefore' becomes 'so' ('so' can mean 'consequently' or 'therefore').
'finish' suggests halving the letters.
'up' cut in half is 'p'.
'so'+'p'='SOP'
'making' is the link.
(Other definitions for sop that I've seen before include "A bribe or appeasement" , "Appeasing bribe" , "Small concession" , "usual way of doing things, initially" , "Propitiatory offering" .)