Not derived or copied (8)
I believe the answer is:
original
'not derived or copied' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for original that I've seen before include "An oil rig (anag)" , "Not copied or imitated" , "New in character or design - not a copy" , "Archetype, master copy" , "The first, not a copy" .)