Veil military hospital gossip after switch of leaders (7)
I believe the answer is:
yashmak
'veil' is the definition.
(yashmak is a kind of veil)
I cannot understand how the rest of the clue works.
(Other definitions for yashmak that I've seen before include "Moslem woman's double veil" , "Facial veil" , "modest assumption" , "Face-veil for Muslim women like shaky ma" , "Veil worn by Muslim women in some countries" .)