Mess initially put together by soldiers (5)
I believe the answer is:
snafu
'mess' is the definition.
(I've seen this in another clue)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for snafu that I've seen before include "Chaotic situation" , "confused activity" , "Slangy acronym meaning in total confusion" , "Chaos (US slang)" , "Chaotic state, mess" .)