Binge over, guy must purge insides (4)
I believe the answer is:
orgy
'binge' is the definition.
(thesaurus)
'over guy must purge insides' is the wordplay.
'over' becomes 'or' (I can't explain this - if you can you should believe this answer much more).
'must purge insides' says to hollow out the word (remove centre letters).
'guy' with its centre removed is 'gy'.
'or'+'gy'='ORGY'
(Other definitions for orgy that I've seen before include "Frenzy; bacchanalia" , "Wild revel" , "wild spree" , "A licentious immoral party" , "Wild overindulgent party" .)