The most common and most likely answer to this crossword clue is the 4 letter word HOCK
I've seen this crossword clue in The Guardian
H
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Buddy explains!
The straight part
We know that "Joint/German wine" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case joint/german wine = hock.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 HOCK mean?
HOCK noun- A Rhenish wine, of a light yellow color, either sparkling or still, from the Hochheim region; often applied to all Rhenish wines.
- The tarsal joint of a digitigrade quadruped, such as a horse, pig or dog.
- Meat from that part of a food animal.
- To disable by cutting the tendons of the hock; to hamstring; to hough.
- Pawn, obligation as collateral for a loan.
- Debt.
- Installment purchase.
- Prison.
- To leave with a pawnbroker as security for a loan.
- To bother; to pester; to annoy incessantly
- To cough heavily, esp. causing uvular frication.