Best final (8)
I believe the answer is:
ultimate
I believe this is a double definition.
'best' is the first definition.
(I've seen this before)
'final' is the second definition.
(similar in meaning)
(Other definitions for ultimate that I've seen before include "Happening at the end of a process, final" , "Happening last" , "Furthest, final" , "Last or concluding element" , "Mutilate in final way" .)