English Reference

Phrasal verb

stay up

Definition

phrasal verb. to go to bed later than usual instead of sleeping.

phrasal verb. to remain awake and refrain from going to bed during the hours when one would normally be asleep. Intransitive in this sense.

Examples

“I often stay up late on Friday nights.”

“The children wanted to stay up to watch the fireworks, but they fell asleep on the sofa.”

“Medical residents frequently stay up for twenty-four hours or more, which can lead to significant cognitive fatigue and increased clinical errors.”

Examples

simple

“I often stay up late on Friday nights.”

contextual

“The children wanted to stay up to watch the fireworks, but they fell asleep on the sofa.”

complex

“Medical residents frequently stay up for twenty-four hours or more, which can lead to significant cognitive fatigue and increased clinical errors.”

Usage

often followed by the adverb 'late' or a prepositional phrase like 'until midnight'.

Teaching tip

contrast with 'sit up' (which implies staying awake while remaining in a seated position) and 'pull an all-nighter' (slang for staying up the entire night to work).

Pitfall

I stayed up to 2 a.m.

I stayed up until 2 a.m.

use 'until' or 'till' to indicate the end time; 'to' is not used with 'stay up' for time duration.

Phrasal verb

Particles

up

Separability

inseparable

Pattern

stay + up

Synonyms

remain awakesit upwait up

Antonyms

go to bedturn inhit the hay

Grammar

Phrasal verbs (introduction)

This entry

Exam level
CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.A2 KeyIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.3.0–4.0TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 2.0–2.524–43TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.225–549
Level
A2 · Elementary
Updated

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