The most common and most likely answer to this crossword clue is the 5 letter word HOUGH
H
O
U
G
H
Buddy explains!
The straight part
We know that "Edinburgh joint" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case edinburgh joint = hough.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 HOUGH mean?
HOUGH noun- The hollow behind the knee.
- To hamstring.
- A piece of land that juts out towards the sea; a promontory.
- Archaic spelling of hoe.
- A piece of land that juts out towards the sea; a promontory.