'Rag Trade' not traditional fashion (4)
I believe the answer is:
rage
'fashion' is the definition.
(rage is a kind of fashion)
'rag trade not traditional' is the wordplay.
'not' indicates named letters should be taken away.
'traditional' becomes 'trad' (abbreviation - especially in music 'trad jazz').
'trade' with 'trad' taken away is 'e'.
'rag'+'e'='RAGE'
(Other definitions for rage that I've seen before include "Uncontrollable anger" , "See red" , "Intense anger" , "spread rapidly" , "Wrath" .)