Muslim face veil (5)
(Other definitions for niqab that I've seen before include "burqa? Not quite" , "Muslim veil" .)
'muslim face veil' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for yashmak that I've seen before include "veil over features" , "Face-veil worn by Muslim women" , "Face-veil for Muslim women like shaky ma" , "Veil concealing face worn by Muslim women" , "Veil worn in public by Muslim women" .)