The most common and most likely answer to this crossword clue is the 6 letter word UROPOD
U
R
O
P
O
D
Buddy explains!
The straight part
We know that "Abdominal appendage" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case abdominal appendage = uropod.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 UROPOD mean?
UROPOD noun- Either of the two posterior abdominal appendages of the lobster, shrimp and some other crustaceans
- The hind part of polarized leukocytes, mostly involved in cell-to-cell interaction, cell activation and apoptosis