The most common and most likely answer to this crossword clue is the 10 letter word SABBATICAL
I've seen this crossword clue in The Times
S
A
B
B
A
T
I
C
A
L
More clues leading to the result SABBATICAL
- Mole finally quits a Baltic base, prepared for leave
- Book club in Calais arranged time for special project
- Leave cab, alas, bit damaged
- Break off with a cabbalist
- Leave as small group entertain on the radio
- Graduates rejected a Baltic cruise in time off
- Leave Italy mostly relaxed after band’s appearance in street
- Waterloo veterans nothing short of stoical about enjoying rest
- Hurt, I blast a cab and leave
Buddy explains!

The straight part
We know that "leave" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case leave = sabbatical.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 SABBATICAL mean?
SABBATICAL noun- An extended period of leave from a person's usual pursuits.
- Relating to the Sabbath / sabbath.
- Relating to a sabbatical.