Part not being performed, a Shakespearean female (6)
I believe the answer is:
portia
'shakespearean female' is the definition.
The definition suggests a singular noun which matches the answer.
'part not being performed a' is the wordplay.
I cannot quite understand how this works, but
'part' could be 'ti' (ti is a kind of part) and 'ti' is present in the answer.
'not' could be 'o' (I've seen this in other clues) and 'o' is found within the answer.
'a' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for portia that I've seen before include "Heiress of The Merchant of Venice" , "Merchant of Venice girl" , "judge" , "Heroine of Shakespeare's ''The Merchant of Venice''" , "She married Bassanio (Merchant of Venice)" .)