The most common and most likely answer to this crossword clue is the 5 plus 5 letter word FALSE ALARM
I've seen this crossword clue in The Sunday Telegraph
F
A
L
S
E
A
L
A
R
M
More clues leading to the result FALSE ALARM
- Panic over swimmer caught in river branch
- River creature with weapon creates unnecessary panic
- A mare falls awkwardly, causing unnecessary anxiety
- A small fear spread, out of unfounded scare
- Prosthetic limb worn by gangster causes unnecessary panic
- Artificial aluminium limb causing needless nervousness
- Fear a small resort experienced: unfounded scare?
- Decline involving water power? It’s not really an emergency
- A large mammal seen in part of country, no real reason for anxiety
- Gangster getting close in rural homestead? Nothing to worry about!
Buddy explains!
The straight part
We know that "no real reason for anxiety" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case no real reason for anxiety = false alarm.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.