Wrongly recasts one in role of Desdemona, say (7)
I believe the answer is:
actress
'one in role of desdemona say' is the definition.
(Desdemona is a female role in Othello)
'wrongly recasts' is the wordplay.
'wrongly' is an anagram indicator (I've seen this in other clues).
'recasts' anagrammed gives 'ACTRESS'.
(Other definitions for actress that I've seen before include "Stage performer" , "One playing" , "Female stage-player" , "Garland perhaps" , "Theatrical female" .)