Extremely large chopper, perhaps (4)
I believe the answer is:
tool
'chopper perhaps' is the definition.
(chopper is a kind of tool)
'extremely large' is the wordplay.
'extremely' becomes 'too' (I've seen this in other clues).
'large' becomes 'l'.
'too'+'l'='TOOL'
(Other definitions for tool that I've seen before include "Pawn" , "Gun" , "Appliance" , "Maybe saw" , "Hand implement" .)