Fifth president (6)
I believe the answer is:
monroe
'fifth president' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for monroe that I've seen before include "No more the blond film star" , "No more the old blond film start" , "Marilyn --, US actress" , "5th US president, James" , "Marilyn - - (films)" .)