The most common and most likely answer to this crossword clue is the 5 letter word VIPER
I've seen this crossword clue in The Guardian
V
I
P
E
R
More clues leading to the result VIPER
- Celebrity royal: a snake!
- Privet cut down, surprisingly revealing snake
- Asp that is without power to puncture old queen?
- Spiteful person used to remove vetness from vindscreen?
- Bigshot meeting the queen is traitor
- Dignitary meeting queen is treacherous type
- Salesperson returning after six is a snake
- Hesitation to meet bigwig, a poisonous type
- A snake and a sneak?
- Privet trimmed unusually as a snake
Buddy explains!

The straight part
We know that "snake" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case snake = viper.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 VIPER mean?
VIPER noun- A venomous snake in the family Viperidae.
- A dangerous, treacherous, or malignant person.
- A person who smokes marijuana.