Difficult clue about northern kinsman (5)
I believe the answer is:
uncle
'kinsman' is the definition.
(I know that uncle is a type of kinsman)
'difficult clue about northern' is the wordplay.
'difficult' indicates anagramming the letters.
'about' indicates putting letters inside.
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'clue' is an anagram of 'ucle'.
'ucle' placed around 'n' is 'UNCLE'.
(Other definitions for uncle that I've seen before include "Grandfather's son" , "Sam, perhaps" , "Male family member" , "Brother of one's parent" , "Dad's brother" .)