Issues instructions for underwear (6)
I believe the answer is:
briefs
This clue is a double definition.
'issues instructions' is the first definition.
'underwear' is the second definition.
(I've seen this before)
'for' is the link.
(Other definitions for briefs that I've seen before include "Gives information and instructions (to)" , "Sets of instructions for lawyers" , "Underpants, knickers" , "Underpants for a lawyer" , "Underwear and lawyer's documents" .)