Dirty edges before horrible family line (7)
I believe the answer is:
dynasty
'family line' is the definition.
(I know that dynasty is a type of family line)
'dirty edges before horrible' is the wordplay.
'edges' says to hollow out the word (remove centre letters) (I've seen 'edges of' mean this).
'before' is a charade indicator (letters next to each other).
'horrible' becomes 'nasty' (I've seen this before).
'dirty' with its centre removed is 'dy'.
'dy'+'nasty'='DYNASTY'
(Other definitions for dynasty that I've seen before include "Sequence of hereditary rulers" , "Sequence of powerful leaders in the same family" , "show" , "Song perhaps" , "Series of hereditary rulers" .)