Finish the season tired ultimately (3)
I believe the answer is:
end
'finish' is the definition.
('end' can be a synonym of 'finish')
'the season tired ultimately' is the wordplay.
'ultimately' indicates one should take the final letters.
The final letters of 'the season tired' are 'END'.
(Other definitions for end that I've seen before include "Game at bowls" , "Culmination" , "Closure" , "Conclusion or goal" , "Cesation, conclusion" .)