Motherly pal seen with royal and northern man (8)
I believe the answer is:
maternal
'motherly' is the definition.
(similar in meaning)
'pal seen with royal and northern man' is the wordplay.
'pal' becomes 'mate' (both can mean a friend).
'seen with' is a charade indicator (letters next to each other).
'royal' becomes 'r' (common abbreviation e.g. RM - Royal Marine).
'and' becomes 'n' (common abbreviation for 'and').
'northern man' becomes 'al' (man's name. I am not sure about the 'northern' bit.).
'mate'+'r'+'n'+'al'='MATERNAL'
Can you help me to learn more?
(Other definitions for maternal that I've seen before include "Motherly" , "Of a mother or motherhood" , "Protective" , "On the mother's side" .)