The most common and most likely answer to this crossword clue is the 8 letter word FOREARMS
I've seen this crossword clue in The Daily Telegraph
F
O
R
E
A
R
M
S
More clues leading to the result FOREARMS
Buddy explains!
The straight part
We know that "Prepares" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case prepares = forearms.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 FOREARMS mean?
FOREARMS noun- The part of the arm between the wrist and the elbow.
- A section of the weapon between the receiver and the muzzle, used to hold the firearm steady.