Northeast men not finished with sibling goddess (7)
I believe the answer is:
nemesis
'goddess' is the definition.
(I've seen this before)
'northeast men not finished with sibling' is the wordplay.
'northeast' becomes 'NE' (abbreviation).
'not finished' means to remove the last letter.
'with' is a charade indicator (letters next to each other).
'sibling' becomes 'sis' (short for sister).
'men' with its last letter taken away is 'me'.
'ne'+'me'+'sis'='NEMESIS'
(Other definitions for nemesis that I've seen before include "Avenging deity" , "An agent of vengeance and retribution" , "The Greek goddess of divine retribution and vengeance" , "Destiny" , "enemy" .)