Work on body producing a military display (6)
I believe the answer is:
tattoo
This clue is a double definition.
'work on body' is the first definition.
(work of art on someone's body)
'a military display' is the second definition.
(I've seen this before)
'producing' is the link.
(Other definitions for tattoo that I've seen before include "display involving military band" , "Drumbeat, or design on skin" , "Military event" , "Indelible decoration on skin" , "Needlework! - performed by soldiers!" .)