Caught in Essex shifting leftovers (6)
I believe the answer is:
excess
'leftovers' is the definition.
(thesaurus)
'caught in essex shifting' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'in' is an insertion indicator.
'shifting' indicates an anagram.
'essex' is an anagram of 'exess'.
'c' inserted into 'exess' is 'EXCESS'.
(Other definitions for excess that I've seen before include "Nothing in it, for the Greeks" , "Glut; surplus" , "Lack of moderation, in drinking say" , "more than enough" , "debauchery" .)