What is the noun of the verb 'depart"?

The noun of the verb "depart" is: departure

Here's a breakdown of the other options:

• Department refers to a division within a larger organization, not the act of leaving.
• Departing is the present participle of the verb "depart," indicating an ongoing action, not a completed action like leaving.
• Departed can be used as a past participle ("They have departed") or as a noun for deceased people (archaic usage). However, in this context, it's not the most general term for the act of leaving.

Therefore, "departure" is the most suitable noun that captures the act or instance of leaving.