Copies or simulates (8)
I believe the answer is:
imitates
I believe this clue is a double definition.
'copies' is the first definition.
(I know this)
'simulates' is the second definition.
('imitate' can be a synonym of 'simulate')
(Other definitions for imitates that I've seen before include "Copies, takes off" , "Apes" , "Copies, simulates" , "Mimics or simulates" .)