The most common and most likely answer to this crossword clue is the 7 letter word VILLEIN
I've seen this crossword clue in The Guardian
V
I
L
L
E
I
N
More clues leading to the result VILLEIN
Buddy explains!

The straight part
We know that "Old countryman" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case old countryman = villein.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 VILLEIN mean?
VILLEIN noun- A feudal tenant.