By whom an autobiography is written? (7)
I believe the answer is:
oneself
'autobiography is written?' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'by whom an' is the wordplay.
'by' says to put letters next to each other.
'whom' becomes 'self' (I can't explain this - if you can you should give a lot more credence to this answer).
'an' becomes 'one'.
'self' put after 'one' is 'ONESELF'.
Can you help me to learn more?
(Other definitions for oneself that I've seen before include "A certain person" , "Mirror image" , "Reflexive pronoun" , "By this, unaided" , "Personal pronoun" .)