The most common and most likely answer to this crossword clue is the 8 letter word SINISTER
I've seen this crossword clue in The Daily Telegraph
S
I
N
I
S
T
E
R
More clues leading to the result SINISTER
- Scary relative touring Northern Ireland
- Malign relative around at home
- Menacing senior nurse holding hip?
- Sloth, for example, tries moving on the left side
- Malign ward supervisor entertaining at home
- Endless wine is knocked back, boding no good
- Nun holding in evil
- Threatening relative outside home
- Menacing woman with habit seen outside home
- Nun holding in evil
Buddy explains!
The straight part
We know that "ominous" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ominous = sinister.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 SINISTER mean?
SINISTER adjective- Inauspicious, ominous, unlucky, illegitimate (as in bar sinister).
- Evil or seemingly evil; indicating lurking danger or harm.
- Of the left side.
- On the left side of a shield from the wearer's standpoint, and the right side to the viewer.
- Wrong, as springing from indirection or obliquity; perverse; dishonest.