Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “sit up”

sit up

verb uk phrasal verb with sit   /sɪt/ (present participle sitting, past tense and past participle sat) us  

(STRAIGHT)

to sit with a straight back: How many times do I have to tell you children to sit up straight?Sitting and standing

(STAY AWAKE)

to stay awake and not go to bed although it is late: [+ -ing verb] The book was so interesting that I sat up all night reading it. I'll be late tonight, so don't sit up for (= wait for) me.Not sleeping and not unconscious

(NOTICE)

informal to show interest or surprise: The news that he was getting married really made her sit up.Excited, interested and enthusiastic
(Definition of sit up phrasal verb, verb from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
What is the pronunciation of sit up?
Browse related topics

You are looking at an entry to do with Paying attention and being careful, but you might be interested in these topics from the Attention and care topic area:

Add Cambridge dictionaries to your browser to your website

Definitions of “sit up” in other dictionaries

Word of the Day

scrumpy

an alcoholic drink made from apples

Word of the Day

Blog

Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More