The most common and most likely answer to this crossword clue is the 6 letter word GREAVE
I've seen this crossword clue in The Guardian
G
R
E
A
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More clues leading to the result GREAVE
Buddy explains!

The straight part
We know that "Provided protection for some soldiers /Provided protection for some soldiers" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case provided protection for some soldiers /provided protection for some soldiers = greave.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 GREAVE mean?
GREAVE noun- A bush; a tree; a grove.
- A bough; a branch.
- A ditch or trench.
- A piece of armour that protects the leg, especially the shin.
- To clean (a ship's bottom); to grave.