Kick out old footballer who can't finish (5)
I believe the answer is:
expel
'kick out' is the definition.
(synonyms)
'old footballer who can't finish' is the wordplay.
'old' becomes 'ex' (prefix meaning former or onetime).
'footballer' becomes 'pele' (Brazilian footballer Pele).
'who can't finish' means to remove the last letter (the word doesn\'t finish).
'pele' with its last letter removed is 'pel'.
'ex'+'pel'='EXPEL'
(Other definitions for expel that I've seen before include "Oust" , "Force to leave" , "Remove from membership" , "Deport" , "Spew" .)