Imposing (9)
'imposing' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for grandiose that I've seen before include "Pretentiously imposing -- organised (anag)" , "Ambitious" , "Ridiculously impressive or imposing" , "Imposing and pompous, dressed in organdies" , "Bombastic" .)
'imposing' is the definition.
(I know that imposing can be written as grand)
This is the entire clue.
(Other definitions for grand that I've seen before include "1000, colloquially" , "Marvellous" , "A slangy PS1,000" , "principal" , "Impressive, large" .)