off-duty

1. Not engaged in or responsible for assigned work.
2. Of or relating to the periods when a person is not engaged in or responsible for assigned work.

At one's post, at work, as in The new nurse was on duty that evening, or The watchman was fired because he was drunk on duty. [Mid-1600s] The antonym, off duty, means "not engaged in one's work," as in Captain Smith was much more amiable when he was off duty. [Mid-1800s]

The adjective has one meaning:

Meaning #1: not performing or scheduled for duties
  Synonyms: off, off duty