Raised support without very noted portrayer of Desdemona, say (4)
I believe the answer is:
diva
'noted portrayer of desdemona say' is the definition.
(a diva might play Desdemona in Othello)
'raised support without very' is the wordplay.
'raised' says the letters should be written in reverse.
'support' becomes 'aid' (synonyms).
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'very' becomes 'v' (abbreviation).
'aid' enclosing 'v' is 'avid'.
'avid' back-to-front is 'DIVA'.
(Other definitions for diva that I've seen before include "Great performer" , "Great singer" , "Top opera singer" , "Successful lady" , "High-maintenance opera singer?" .)