Dream about safe saint (9)
I believe the answer is:
fantasise
'dream' is the definition.
('dream'->'fantasize' is in my internal thesaurus and 'ize'->'ise')
'about safe saint' is the wordplay.
'about' indicates anagramming the letters.
'safe'+'saint'='safesaint'
'safesaint' anagrammed gives 'FANTASISE'.
(Other definitions for fantasise that I've seen before include "Indulge in imagination unrestricted by reality" , "Imagine" .)