Possibly Miss Joan? (4)
I believe the answer is:
sims
'joan?' is the definition.
Both the answer and definition are singular nouns.
Maybe there's an association between them I don't understand?
'possibly miss' is the wordplay.
'possibly' is an anagram indicator.
'miss' with letters rearranged gives 'SIMS'.
Can you help me to learn more?
(Other definitions for sims that I've seen before include "Author of 'In the Workhouse: Christmas Day'" , "One who wrote about a Christmas Day" .)