The most common and most likely answer to this crossword clue is the 8 letter word PERICARP
I've seen this crossword clue in The Times
P
E
R
I
C
A
R
P
More clues leading to the result PERICARP
Buddy explains!
The straight part
We know that "wall of fruit" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case wall of fruit = pericarp.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 PERICARP mean?
PERICARP noun- The outermost layer, or skin, of a ripe fruit or ovary.
- The outer layer of any thing.