"Sorry, I have a ___ commitment"

PRIOR

Think of a word that means something scheduled earlier or more important than what’s being declined.

This clue plays on a common phrase people use when turning down plans. The blank suggests a word meaning "earlier" or "more important," and "prior" fits perfectly—it literally means something that comes before in time or rank. The phrasing mimics real-life excuses, like when someone says they can’t attend because of a "prior commitment," making the answer feel natural. No tricks here, just straightforward word choice.