The most common and most likely answer to this crossword clue is the 1 letter word Q
I've seen this crossword clue in The Guardian
Q
More clues leading to the result Q
- Stick to clean joke: time for second
- Kernel from down under article put on antelope for one in desert
- Q
- is our favourite today.
- and 18a were our last two to get sorted and stretched our solving time considerably.
- is our favourite for today.
- gets our biggest tick today.
- is our favourite today. We had ‘mendicant’ from Jay recently and enjoyed meeting it again with a slightly different meaning.
- had us working hard, with a real d’oh moment when we understood it, so that is our favourite today.
- was our last one in and is our favourite today.
Buddy explains!

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 Q mean?
Q noun- Conditional qualification
- Question