Some fashionistas smoke dope (3)
I believe the answer is:
ass
'dope' is the definition.
(both can mean a stupid person)
'some fashionistas smoke' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'ASS' can be found hidden inside 'fashionistas smoke'.
(Other definitions for ass that I've seen before include "Transport for a wise man - or a fool" , "Foolish person; animal" , "Idiotic animal" , "Animal; fool" , "Trump's behind" .)