[H]e came to this country in the service of an English gentleman, whom he was obliged to quit through the malice of the valet de chambre, who taking advantage of the young man's being overtaken with liquor on the last St.Andrew's day, turned him off, on the pretext of his being an habitual drunkard.1789, John Moore, Zeluco, Valancourt, published 2008, page 273:
2
To power down, to switch off, to put out of operation, to deactivate (an appliance, light, mechanism, functionality etc.).
Turn off the machine and unplug it when you leave.
"Will it ever stop?" Yo, I don't know / Turn off the lights, and I'll glow1989, “Ice Ice Baby”, in Hooked, performed by Vanilla Ice:
1 more example
Hello, IT. Have you tried turning it off and turning it on again? Ok. Well, are you sure that it's plugged in?2006 February 17, Graham Linehan, The IT Crowd, season 1, episode 4:
3
Usually, Of a machine To become deactivated; to become powered down.
My computer turned off!
4
To rotate a tap or valve so as to interrupt the outflow of liquid or gas.
Remember to turn the tap off once you've finished so you don't waste water.
5
To repulse, disgust, or discourage (someone).
Cigarette smoking really turns me off.
Better be a gentleman, or you'll turn me off1986, “Nasty”, in Control, performed by Janet Jackson:
1 more example
"They are turning people off travelling. And the removal of catering on such a long-distance route is just bonkers."2021 December 29, Paul Clifton, “"Crisis" on the West of England line”, in RAIL, number 947, page 35:
"Pardon my clumsiness," he said to the lady. "I am, unfortunately, quite blind. But," he added, with a smile, to turn off the mishap, "even a blind man must have a house."1914, Ernest Bramah, Max Carrados:
The fell had not only put its cap on, it was drawn down over its white face as that other white cap, still more terrible to look upon, covers the features of the poor wretch about to be "turned off" on the gallows.1890, James Payn, The Burnt Million, volume 2, page 63: