John or Barbara? (5)
I believe the answer is:
major
'barbara?' is the definition.
Both the definition and answer are singular nouns.
Maybe you can see a link between them that I can't see?
'john or' is the wordplay.
'john' becomes 'maj' (I can't justify this - if you can you should give a lot more credence to this answer).
'maj'+'or'='MAJOR'
Can you help me to learn more?
(Other definitions for major that I've seen before include "Large" , "Not minor" , "Conservative PM" , "Important - ex-PM" , "1 down's predecessor" .)