Design military display (6)
I believe the answer is:
tattoo
This clue is a double definition.
'design' is the first definition.
(tattoo is a kind of design)
'military display' is the second definition.
(I've seen this before)
(Other definitions for tattoo that I've seen before include "Personal design" , "Skin inking" , "Military signal/display" , "Drum signal; skin mark" , "display involving military band" .)