Royals upset northern woman (7)
I believe the answer is:
rosalyn
'woman' is the definition.
'royals upset northern' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'royals' is 'rosaly' which is within the answer.
'northern' could be 'n' (abbreviation e.g. N. Ireland) and 'n' is present in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for rosalyn that I've seen is " Does this girl slay Ron?".)