unscheduled

/ənˈskɛʤuld/

Something unscheduled is not planned for or anticipated. If your mother shows up at your door unscheduled, hope that you've been keeping the place nice and clean since you won't have time to tidy up before her arrival.

The word unscheduled describes something that is not planned or scheduled in advance, as seen by the prefix un- meaning "not." An unscheduled interruption of a television program might mean there's breaking news that you need to hear. An unscheduled delay of a flight might mean you're stuck in the airport for hours. Whatever it may be, something that's unscheduled happens without your expecting it, which means it might very well throw you off your regular routine or schedule.

Definitions of unscheduled

1. adjective

   not scheduled or not on a regular schedule
   “an unscheduled meeting”

   “the plane made an unscheduled stop at Gander for refueling”

   synonyms:

   extra, special

   added to a regular schedule

   forced

   made necessary by an unexpected situation or emergency

   antonyms:

   scheduled

   planned or scheduled for some certain time or times

   regular

   regularly scheduled for fixed times