Preparing rip-off dynasty (7)
I believe the answer is:
priming
'preparing' is the definition.
(priming is a kind of preparing)
'rip-off dynasty' is the wordplay.
'off' indicates anagramming the letters.
'dynasty' becomes 'ming' (I've seen this before).
'rip' with letters rearranged gives 'pri'.
'pri'+'ming'='PRIMING'
(Other definitions for priming that I've seen before include "Briefing" , "Preparing for firing" .)