Is she twice a mother? (5)
I believe the answer is:
madam
'is she' is the definition.
I can't judge whether this definition defines the answer.
'twice a mother?' is the wordplay.
'twice' becomes 'ma' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'a mother?' becomes 'dam' (female parent of an animal).
'ma'+'dam'='MADAM'
Can you help me to learn more?
(Other definitions for madam that I've seen before include "Titled lady" , "Leader of House of Congress" , "Palindrome used in speaking politely to a woman" , "Woman running a brothel" , "What you would call a female customer (or a spoiled girl!)" .)