The most common and most likely answer to this crossword clue is the 5 plus 4 letter word DONOR CARD
I've seen this crossword clue in The Guardian
D
O
N
O
R
C
A
R
D
More clues leading to the result DONOR CARD
- What’s carried in case of death of fellow killer at sea, by the way
- What identifies one intending to be late to help others?
- London or Cardiff must hold record of this vital medical authorisation
- Do move, or doctor can with authorisation to use body parts!
- Fund raising receipt found in Mount Snowdon or Cardigan
Buddy explains!
The straight part
We know that "authorisation to use body parts" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case authorisation to use body parts = donor card.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.