The most common and most likely answer to this crossword clue is the 9 letter word UNMARRIED
I've seen this crossword clue in The Times
U
N
M
A
R
R
I
E
D
More clues leading to the result UNMARRIED
- Not spoiled, I kept single
- Perfect to assume one is single
- Single mistake in a murder
- Single fluid in eardrum
- Single university memory returned when in diner, wandering
- Admire run — scrambled single
- Single man, ruder possibly, maintaining ego
- Single admirer spoilt by a Parisian
- Single drum in ear, vibrating
- Bowled underarm to restrict one single
Buddy explains!

The straight part
We know that "single" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case single = unmarried.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 UNMARRIED mean?
UNMARRIED noun- An unmarried person.
- Having no husband or wife.