Actress Russo or philosopher Descartes (4)
I believe the answer is:
rene
This clue is a double definition.
'actress russo' is the first definition.
(I've seen this in another clue)
'philosopher descartes' is the second definition.
(I've seen this in another clue)
(Other definitions for rene that I've seen before include "- Lalique, glass artist" , "-- Magritte, artist" , "- Descartes, French mathematician" .)