Synonyms of the word

unscheduled

• adj. Not scheduled; impromptu.

extra

• adj. Beyond what is due, usual, expected, or necessary; extraneous; additional; supernumerary.
• adj. (dated) Extraordinarily good; superior.
• adj. (Canada, US, slang) Over-the-top; going beyond what is normal or expected, often in a dramatic mannner.
• adv. (informal) To an extraordinary degree.
• n. (cricket) A run scored without the ball having hit the striker's bat - a wide, bye, leg bye or no ball;…
• n. An extra edition of a newspaper, which is printed outside of the normal printing cycle.
• n. (acting) A supernumerary or walk-on in a film or play.
• n. Something of an extra quality or grade.

forced

• v. simple past tense and past participle of force.
• adj. Obtained forcefully, not naturally.
• adj. Opened or accessed using force.

special

• adj. Distinguished by a unique or unusual quality.
• adj. Of particular interest or value; certain; dear; beloved; favored.
• adj. (euphemistic) Retarded; mentally handicapped.
• adj. Constituting or relating to a species.
• adj. Chief in excellence.
• adj. (military) Of or related to special forces.
• n. A reduction in consumer cost (usually for a limited time) for items or services rendered.
• n. (broadcasting) Unusual or exceptional episode of a series.
• n. (Britain, colloquial) A special constable.
• n. Anything that is not according to normal practice, plan, or schedule, as an unscheduled run of transportation…
• n. (video games) Special move.
• v. (nursing) To supervise a patient one-on-one.

unexpected

• adj. Not expected, anticipated or foreseen.