The most common and most likely answer to this crossword clue is the 6 letter word JACKAL
I've seen this crossword clue in The Daily Telegraph
J
A
C
K
A
L
More clues leading to the result JACKAL
- “Every dog has his day” — including this wild one?
- . Jill’s partner with a painful bottom canine
- Raise a large predatory animal
- Means to raise a large wild animal
- Wild animal in a lake, shown on card
- Knave joining gangster, a beast
- Scavenger, one among crew most of all
- Names of two men hunting animal in Africa
- Animal with two names
- Device for lifting a large beast
Buddy explains!

The straight part
We know that "a beast" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a beast = jackal.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 JACKAL mean?
JACKAL noun- Any of certain wild canids of the genus Canis, native to the tropical Old World and smaller than a wolf.
- A person who performs menial/routine tasks, a dogsbody.
- A person who behaves in an opportunistic way; especially a base collaborator.
- A jack (the playing card).
- To perform menial or routine tasks