English

Noun

dog sleep ‎(uncountable)

1. A shallow sleep; a pretended sleep. Dogs seem to sleep with "one eye open."
   • 1841, Charles Dickens, chapter 3, in Barnaby Rudge:

     nodding in his dog sleep

References

• Brewer, Ebenezer Cobham, Brewer's Dictionary of Phrase and Fable, 1898.