The most common and most likely answer to this crossword clue is the 3 letter word NON
I've seen this crossword clue in The Daily Telegraph
N
O
N
More clues leading to the result NON
- Poor men on novel grant not involving elected rulers
- New on street, work without break
- Cheap wine - inn gave ton away
- No bridge partners surpass uninterruptedly
- A number dash across drive, avoiding spillage
- One in van going round with venison requiring no cutting
- Like type of book in which poem is given new heading
- One craven emperor injecting on heroin
- Noted sinner, after correction, is not staying
- No fool, involving academic in US charity
Buddy explains!
The straight part
We know that "day and night" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case day and night = non.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 NON mean?
NON adverb- To no extent, in no way.
- Not at all, not very.
- No, not.