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sit up

intransitive verb

Definition of sit up

  1. 1a :  to rise from a lying to a sitting positionb :  to sit with the back erect

  2. 2 :  to show interest, alertness, or surprise <sit up and take notice>

  3. 3 :  to stay up after the usual time for going to bed

13th Century

First Known Use of sit up

13th century

Seen and Heard

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a very small amount

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