The most common and most likely answer to this crossword clue is the 9 letter word BARBARISM
I've seen this crossword clue in The Times
B
A
R
B
A
R
I
S
M
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The straight part
We know that "Uncivilised nature" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case uncivilised nature = barbarism.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 BARBARISM mean?
BARBARISM noun- A barbaric act.
- The condition of existing barbarically.
- A word hybridizing Ancient Greek and Latin or other heterogeneous roots.
- An error in language use within a single word, such as a mispronunciation.