Fine clue, cryptic, about northern power (9)
I believe the answer is:
influence
'power' is the definition.
(I know that influence is a type of power)
'fine clue cryptic about northern' is the wordplay.
'cryptic' indicates an anagram (a cryptic or obscure order of the letters).
'about' indicates putting letters inside.
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'fine'+'clue'='fineclue'
'fineclue' anagrammed gives 'ifluence'.
'ifluence' placed around 'n' is 'INFLUENCE'.
(Other definitions for influence that I've seen before include "Power to affect persons or events" , "Weight" , "Pull, clout" , "Clue in fen (anag.)" , "Sway, dominance" .)