Cover or envelop (6)
I believe the answer is:
shroud
I believe this clue is a double definition.
'cover' is the first definition.
(I've seen this before)
'envelop' is the second definition.
(shrouding is a kind of enveloping)
(Other definitions for shroud that I've seen before include "Envelop (in cloud, for instance)" , "Conceal from view" , "hide" , "Cloth wrap for corpse" , "Covering shift" .)