Former prince of Monaco (7)
I believe the answer is:
rainier
'former prince of monaco' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for rainier that I've seen before include "Former prince of Monaco" , "Prince of Monaco, married to Grace Kelly, d. 2005" , "This is more likely to pour down" , "Volcano in Washington" , "Prince . . . . . . . rules Monaco" .)