Playing Eton fives -- but not fit, however (4,2)
I believe the answer is:
even so
'however' is the definition.
(synonyms)
'playing eton fives but not fit' is the wordplay.
'playing' is an anagram indicator.
'but not' suggests deleting specific letters.
'eton'+'fives'='etonfives'
'etonfives' with 'fit' taken out is 'eonves'.
'eonves' is an anagram of 'EVEN SO'.
(Other definitions for even so that I've seen before include "Despite that, nevertheless" , "anyway" , "however" , "yet" , "'Despite, still (4,2)'" .)