The most common and most likely answer to this crossword clue is the 7 letter word MARCHER
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The straight part
We know that "soldier, perhaps" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case soldier, perhaps = marcher.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 MARCHER mean?
MARCHER noun- An inhabitant of a march (border country); specifically, a marcher lord.
- A border territory, a march (now only in (attributive) use).
- One who marches; one who participates in a march.