Stop media manipulation happening (7)
I believe the answer is:
prevent
'stop' is the definition.
(I've seen this before)
'media manipulation happening' is the wordplay.
'media manipulation' becomes 'PR' (public relations).
'happening' becomes 'event' (I've seen this in another clue).
'pr'+'event'='PREVENT'
(Other definitions for prevent that I've seen before include "Stop, avert" , "Stop (an action)" , "Stop, hinder" , "Keep from happening" , "Stop from happening" .)