The most common and most likely answer to this crossword clue is the 3 plus 5 letter word ALL CLEAR
I've seen this crossword clue in Independent
A
L
L
C
L
E
A
R
More clues leading to the result ALL CLEAR
- Everyone understood air raid warden's signal
- Wartime signal that would not be misunderstood?
- Thoroughly understood there is no danger
- Leaving no room for doubt following every sign it’s OK
- Safe signal fully understood
- A couple of lines with Large Earl in motor and things are ok!
- ARP signal everyone understood
- No one doubts what this signal means
- Pass over after everyone gets permission to proceed
- Unmistakable support for everyone telling us to come out
Buddy explains!

The straight part
We know that "things are ok" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case things are ok = all clear.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 ALL CLEAR mean?
ALL CLEAR noun- A sign or signal indicating that a hindrance or danger is clear.