Cutting heroin with family from Dallas (6)
I believe the answer is:
hewing
'cutting' is the definition.
'heroin with family from dallas' is the wordplay.
'heroin' becomes 'h' (synonyms).
'with' is a charade indicator (letters next to each other).
'family from dallas' becomes 'ewing' (Ewing family from US soap Dallas).
'h'+'ewing'='HEWING'
(Other definitions for hewing that I've seen before include "process to remove trees?" , "taking a cut" .)