The most common and most likely answer to this crossword clue is the 5 letter word BITER
I've seen this crossword clue in Financial Times
B
I
T
E
R
More clues leading to the result BITER
Buddy explains!
The straight part
We know that "vicious dog" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vicious dog = biter.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 BITER mean?
BITER noun- The act of biting.
- The wound left behind after having been bitten.
- The swelling of one's skin caused by an insect's mouthparts or sting.
- A piece of food of a size that would be produced by biting; a mouthful.
- Something unpleasant.
- An act of plagiarism.
- A small meal or snack.
- Aggression
- The hold which the short end of a lever has upon the thing to be lifted, or the hold which one part of a machine has upon another.
- A cheat; a trick; a fraud.
- A sharper; one who cheats.
- A blank on the edge or corner of a page, owing to a portion of the frisket, or something else, intervening between the type and paper.
- A cut, a proportion of profits; an amount of money.
- A fish that tends to take bait.
- A stone that barely touches the outside of the house.
- One who copies someone else's work, style or techniques, especially in hip-hop.
- A cheat or fraudster.
- A zombie.
- (in combination) Something (a data unit, machine etc.) with a width of a specified amount of bits.