Military display of design on skin (6)
I believe the answer is:
tattoo
I believe this is a double definition.
'military display' is the first definition.
(I've seen this before)
'design on skin' is the second definition.
(I've seen this in another clue)
'of' acts as a link.
(Other definitions for tattoo that I've seen before include "that leaves a permanent impression on one" , "Drum signal; skin marking" , "Indelible picture or design on skin" , "Military evening signal" , "Design marked on skin" .)