The most common and most likely answer to this crossword clue is the 6 letter word TWEEDY
I've seen this crossword clue in Independent
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More clues leading to the result TWEEDY
- Like heavy material getting thin after short time
- Like a country gentleman, initially thin and weak
- Frail, after time dressing for the outdoor life?
- Like country gentry, ultimately not wimpish!
- Ultimately unkempt and feeble, as country gentleman may be?
- Precious, extremely dainty – but ready for the outdoors?
- Typical of country gent, tense and far from robust
- Tense and feeble, like the rural upper classes?
- Aristocrat ultimately insignificant like an upper-class hearty?
- Wimp with extremely tatty clothing of coarse cloth
Buddy explains!

The straight part
We know that "like countryside alliance …" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case like countryside alliance … = tweedy.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 TWEEDY mean?
TWEEDY adjective- (of clothing) made of tweed, or having a similar rough texture
- (of a person) wearing tweed clothing
- (of a person) preppy