sit up

verb

Definition of sit up

  1. intransitive verb
  2. 1a :  to rise from a lying to a sitting positionb :  to sit with the back erect

  3. 2 :  to show interest, alertness, or surprise sit up and take notice

  4. 3 :  to stay up after the usual time for going to bed

First Known Use of sit up

13th century


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