The most common and most likely answer to this crossword clue is the 6 letter word OXHIDE
I've seen this crossword clue in Financial Times
O
X
H
I
D
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More clues leading to the result OXHIDE
Buddy explains!

The straight part
We know that "leather" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case leather = oxhide.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 OXHIDE mean?
OXHIDE noun- The skin (hide) of an ox.
- Leather made from the hide of an ox.