No editor — and no editorial? (10)
I believe the answer is:
nonfiction
'editorial?' is the definition.
(editorial is a kind of nonfiction)
'no editor and no' is the wordplay.
'no editor' becomes 'fiction' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'and' means one lot of letters go next to another.
'no' becomes 'non' (I've seen this in other clues).
'fiction' after 'non' is 'NONFICTION'.
Can you help me to learn more?
(Another definition for nonfiction that I've seen is " As a writer, you couldn't make it up!".)
