Promotional overkill (4)
I believe the answer is:
hype
'promotional overkill' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for hype that I've seen before include "Shrewd publicity" , "Extravagant promotion of a person or product" , "Overblown publicity" , "Puffery" , "A promoter" .)