Garment for women in mind (5)
I believe the answer is:
'mind' is the definition.
'garment for women in' is the wordplay.
'garment for women' becomes 'bra' (underwear worn by women).
(Other definitions for brain that I've seen before include "Intellectual capacity", "Intellectual ability", "Clever person", "Control centre of nervous system", "It's in the skull".)