The most common and most likely answer to this crossword clue is the 5 letter word LEAVE
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More clues leading to the result LEAVE
Buddy explains!

The straight part
We know that "Depart" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case depart = leave.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 LEAVE mean?
LEAVE verb- To have a consequence or remnant.
- To depart; to separate from.
- To transfer something.
- To remain (behind); to stay.
- To stop, desist from; to "leave off" (+ noun / gerund).
- The action of the batsman not attempting to play at the ball.
- The arrangement of balls in play that remains after a shot is made (which determines whether the next shooter — who may be either the same player, or an opponent — has good options, or only poor ones).
- Permission to be absent; time away from one's work.
- Permission.
- Farewell, departure.
- To give leave to; allow; permit; let; grant.
- To produce leaves or foliage.
- To raise; to levy.