Ultimate, last (5)
I believe the answer is:
final
I believe this clue is a double definition.
'ultimate' is the first definition.
(similar in meaning)
'last' is the second definition.
(I know that last can be written as final)
(Other definitions for final that I've seen before include "Conclusive" , "Last in a series of games or contests" , "The last exam or leg of competition" , "Coming at the end" , "Last match in a competition" .)