Primarily poor rating for movie trailer (7)
I believe the answer is:
preview
'trailer' is the definition.
(I've seen this before)
'primarily poor rating for movie' is the wordplay.
'primarily' indicates taking the first letters.
'rating for' becomes 'revie' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'movie' becomes 'W' (W, film about George W Bush).
The initial letter of 'poor' is 'p'.
'p'+'revie'+'w'='PREVIEW'
Can you help me to learn more?
(Other definitions for preview that I've seen before include "early show" , "special showing" , "Foretaste" , "Preliminary showing" , "A showing before opening night" .)