Mint and cinnamon, finally, included in concoction (5-3)
I believe the answer is:
brand-new
'mint' is the definition.
(thesaurus)
'and cinnamon finally included in concoction' is the subsidiary indication.
'finally' suggests the final letters.
'included in' means one lot of letters goes inside another.
'concoction' becomes 'brew' (I've seen this before).
The last letter of 'cinnamon' is 'n'.
'and'+'n'='andn'
'andn' going inside 'brew' is 'brandnew'.
(Other definitions for brand-new that I've seen before include "Just out of the packet!" , "Pristine, never been used" , "Completely unused" , "Hot off the production line" , "In mint condition" .)