The most common and most likely answer to this crossword clue is the 5 letter word OMENS
I've seen this crossword clue in The Daily Telegraph
O
M
E
N
S
More clues leading to the result OMENS
- At front of Gents, old signs
- Signs blokes placed in centre of Crosby
- Workers put in very large signs
- Submarine’s first captain comes up to deliver warnings
- Signs small fish is coming to the surface
- The point in some strange portents
- Signs over “Gents'”
- Old fellows beginning to see signs of things to come
- Swimmer in film, returning at end of Jaws, giving warnings
- Warnings thus rejected, soldiers will be trapped
Buddy explains!
The straight part
We know that "warning signs" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case warning signs = omens.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 OMENS mean?
OMENS noun- Something which portends or is perceived to portend either a good or evil event or circumstance in the future, or which causes a foreboding; a portent or augury.
- A thing of prophetic significance.
- To be an omen of.
- To divine or predict from omens.