The most common and most likely answer to this crossword clue is the 7 letter word BALEFUL
I've seen this crossword clue in Independent
B
A
L
E
F
U
L
More clues leading to the result BALEFUL
- A lot of straw perhaps making one unhappy
- Bitter British beer not all drunk
- Second-rate beer? Drunk endlessly threatening
- Malignant contents of package?
- Menacing bouncer taking notice of you at last
- British beer’s strong, almost menacing
- Threatening to have no more room for packages?
- Ominous amount of hay?
Buddy explains!

The straight part
We know that "threatening" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case threatening = baleful.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 BALEFUL mean?
BALEFUL adjective- Portending evil; ominous.
- Miserable, wretched, distressed, suffering.