The most common and most likely answer to this crossword clue is the 7 letter word REDBACK
I've seen this crossword clue in The Guardian
R
E
D
B
A
C
K
More clues leading to the result REDBACK
Buddy explains!
The straight part
We know that "Victorian poisoner" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case victorian poisoner = redback.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 REDBACK mean?
REDBACK noun- A venomous spider, Latrodectus hasselti, endemic to Australia.
- A brown and white sandpiper, Calidris alpina, native to the Northern Hemisphere; the dunlin.
- The yuan (CNY), the currency of the People's Republic of China (Red Chinese money)