Bash organised for pretentious (9)
I believe the answer is:
grandiose
'pretentious' is the definition.
(similar in meaning)
'bash organised' is the wordplay.
'bash' indicates anagramming the letters.
'organised' with letters rearranged gives 'GRANDIOSE'.
'for' acts as a link.
(Other definitions for grandiose that I've seen before include "affected" , "Impressive, magnificent" , "Bombastic" , "Pretentiously impressive" , "Ridiculously impressive or imposing" .)