The most common and most likely answer to this crossword clue is the 6 letter word FIRKIN
I've seen this crossword clue in Independent
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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 FIRKIN mean?
FIRKIN noun- A varying measure of capacity, usually being a quarter of a barrel; specifically, a measure equal to nine imperial gallons.
- A small wooden vessel or cask of indeterminate size, used for butter, lard, etc.
- A weight measure for butter, equalling 56 pounds.