THE AUTHENTIC—AND SIMPLE—ORIGIN OF ‘SLEEP TIGHT’ In the colloquial phrase sleep tight, used when parting for the night or at bedtime, the adjective tight is used as an adverb meaning soundly, i.e. deeply and without disturbance, as in the combination tight asleep.
The earliest instance of tight asleep that I have found is from the following paragraph published in The Daily Morning Post (Pittsburgh, Pennsylvania) of Tuesday 16th March 1847:
A child was “found missing” one day last week by a good mother up town. The bell was brought into requisition, the dreadful notes of which stirred up the sympathy of the neighborhood, while the lady herself chimed in most frantically. This lasted for some time—say an hour—when the poor little dear was seen emerging from beneath a bed where it had been tight asleep. “All’s well that ends well.”
The earliest occurrence of sleep tight that I have found is from the Carson Daily Appeal (Carson City, Nevada) of Sunday 17th August 1873:
Case of Gin.—Tom McWharton was up, yesterday, arraigned in Police Court for having pressed his tanzy too closely and fallen to sleep tight in a public place.
The second-earliest instance that I have found is from an article about an earthquake that had occurred in Louisville, Kentucky, published in the Daily Press and Dakotaian (Yankton, South Dakota) of Thursday 5th October 1876:
The people from the different portions of the city met each other on the street and told their experience. One was a doctor, who usually sleeps tight, unless called to see a patient. The rumbling and shaking awakened him.
