With an imitation cover, or awning (6)
I believe the answer is:
canopy
'awning' is the definition.
(I've seen this before)
'with an imitation' is the wordplay.
'with' means one lot of letters goes inside another.
'imitation' becomes 'copy' (I've seen this in another clue).
'an' placed within 'copy' is 'CANOPY'.
'cover or' is the link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for canopy that I've seen before include "Ornamental awning" , "Hangong cover as over a bed" , "Ornamental covering" , "Covering over four-poster, etc" , "Cloth covering" .)