His turned up nose has no point, ultimately (3)
I believe the answer is:
son
'his turned up nose has no' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'point ultimately' is the wordplay.
'point' becomes 's' (South).
'ultimately' becomes 'on' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
's'+'on'='SON'
Can you help me to learn more?
(Other definitions for son that I've seen before include "The kind of child" , "Express paper" , "Male descendant" , "Young boy" , "Male offspring" .)