Duplicate (6,4)
There are a few possibilities for this:
carbon copy
'duplicate' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for carbon copy that I've seen before include "Exact replica" , "Wrong" , "Exact duplicate" , "Something identical" .)
'duplicate' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for copy that I've seen before include "Text for an article" , "transcription" , "Reproduce" , "Material for publication" , "written for paper" .)
'duplicate' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for same that I've seen before include "Equal in amount or value" , "If - be the food of love, play on (Twelfth Night)" , "Aforesaid" , "Identical, not different" , "uniform" .)
'duplicate' is the definition.
(I know that twin is a type of duplicate)
This is the entire clue.
(Other definitions for twin that I've seen before include "Castor or Pollux?" , "Identical or very similar" , "One of a similar pair" , "One of two born together" , "Identical sibling" .)
'duplicate' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for redo that I've seen before include "Redecorate or repeat action" , "Decorate (eg a room) again" , "Fashion again" , "Perform (action) again" , "Create again" .)