unscheduled

unscheduled — adjective

1. happening or done without having been added to a plan or calendar in advance — f

1.adjectiveB1
Definition

happening or done without having been added to a plan or calendar in advance — for example, when a train makes an unscheduled stop or a team holds an unscheduled practice session.

Example

The bus made an unscheduled stop near the park to let Diya off.

collocation: make an unscheduled stop

An unscheduled power cut left the Watanabe family without electricity during dinner.

collocation: unscheduled power cut

Common collocations
  • unscheduled stop
  • unscheduled meeting
  • unscheduled delay
  • unscheduled visit
  • unscheduled flight
  • unscheduled power cut
  • unscheduled maintenance
  • unscheduled landing
Synonyms
  • unplanned

    the closest synonym; slightly broader in scope, also used for things that simply lack a plan

  • impromptu

    suggests something done on the spur of the moment, often creative or social, with no preparation at all

  • ad hoc

    more formal; used for arrangements created for a specific purpose, often in professional contexts

  • spontaneous

    emphasises a natural impulse or desire rather than an omission from a timetable

Antonyms
  • scheduled

    the exact opposite; planned and set for a fixed time

  • planned

    arranged in advance; broader than scheduled

  • prearranged

    agreed upon before the event

Grammar Patterns

unscheduled + noun

Usage Note

Almost always used before a noun (attributive position). The opposite is scheduled. Since unscheduled describes a binary state — either something was on a plan or it was not — it is rarely used with degree adverbs like 'very' or 'quite.'

Common Mistakes

I made an unscheduled appointment with my dentist.
I made a last-minute appointment with my dentist.
Unscheduled describes something that happens without being on a plan at all, not something you deliberately arranged at short notice.
The heavy rain was completely unscheduled.
The heavy rain was completely unexpected.
Rain cannot be put on a calendar, so 'unscheduled' does not apply. Use 'unexpected' for surprising natural events.

Word family

Synonym discussion

Sense: adjective/1

All four words describe something that happens without prior arrangement, but they differ in how and why it happens. Unplanned is the broadest term — it simply states that no plan existed, without suggesting a reason. Impromptu often has a positive or creative feel, like an impromptu speech or a jam session. Ad hoc is formal and practical, used for arrangements created to solve a specific problem, such as an ad hoc committee. Spontaneous emphasises a natural desire or impulse rather than an omission — a spontaneous hug is different from an unscheduled meeting. In everyday speech, unscheduled is most natural for things that normally appear on a timetable but do not today: 'The airline offered compensation for the unscheduled delay.'

unplannedimpromptuad hocspontaneous ↗

Common collocations

Nouns

Phrases

  • make an unscheduled stop
  • call an unscheduled meeting
  • cause an unscheduled delay

Prepositions

  • unscheduled for [date/time]

Etymology

LatinFrenchEnglish

Formed in English by adding the prefix un- (meaning 'not') to scheduled, the past participle of the verb schedule. The verb schedule comes from the noun schedule, which entered English through Old French cedule from Late Latin schedula, meaning 'a small piece of paper' — originally a written slip or note listing items in order.