The most common and most likely answer to this crossword clue is the 10 letter word CAMOUFLAGE
I've seen this crossword clue in The Times
C
A
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More clues leading to the result CAMOUFLAGE
- One way to hide fluorine, in mashed guacamole
- Came across old uniform cloth for staff in military design
- Cover Macau golf out east
- Hide male in a foul cage after beating
- Caught with a sign of discontent about national symbol? Disguise required!
- Call UFO image phony – not fine one, a sort of optical trick?
- French author talked standard English to blend in
- Arrived to arrest Unionist draped in old Irish tricolour perhaps as disguise
- Disguise chef finally having mixed guacamole outside
- Arrived, carrying round university emblem, in disguise
Buddy explains!

The straight part
We know that "military design" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case military design = camouflage.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CAMOUFLAGE mean?
CAMOUFLAGE noun- A disguise or covering up.
- The act of disguising.
- The use of natural or artificial material on personnel, objects, or tactical positions with the aim of confusing, misleading, or evading the enemy.
- A pattern on clothing consisting of irregularly shaped patches that are either greenish/brownish, brownish/whitish, or bluish/whitish, as used by ground combat forces.
- Resemblance of an organism to its surroundings for avoiding detection.
- Clothes made from camouflage fabric, for concealment in combat or hunting.
- To hide or disguise something by covering it up or changing the way it looks.