The most common and most likely answer to this crossword clue is the 10 letter word PUFFERFISH
I've seen this crossword clue in The Guardian
P
U
F
F
E
R
F
I
S
H
Buddy explains!
The straight part
We know that "poisonous bite" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case poisonous bite = pufferfish.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 PUFFERFISH mean?
PUFFERFISH noun- Any species of fish of the family Tetraodontidae that have the ability to inflate themselves to a globe several times their normal size by swallowing water or air when threatened; puffer, blowfish, swellfish, balloonfish, globefish.
- A delicacy popular in Japan served raw as sushi that may, if improperly prepared, contain deadly levels of neurotoxins; (Japanese) fugu.