Spaniard possibly sore about a bit of fun (5)
I believe the answer is:
senor
'spaniard' is the definition.
('mister' in Spanish)
'possibly sore about a bit of fun' is the wordplay.
'possibly' indicates an anagram.
'about' means one lot of letters goes inside another.
'a bit of fun' becomes 'n' (I can't justify this - if you can you should believe this answer much more).
'sore' is an anagram of 'seor'.
'seor' enclosing 'n' is 'SENOR'.
Can you help me to learn more?
(Other definitions for senor that I've seen before include "Spanish for Mr" , "Spanish title" , "Snore like Spanish gent" , "Man in Havana ?" , "address on the Costa del Sol" .)