Unknown, but lexicographer Eric Partridge (1894-1976) speculated that it may be a corruption of cease. Originally thieves' cant.
In his Vocabulary of the Flash Language, author and former convict James Hardy Vaux (1782-?) defined cheese it as synonymous with stash it and stow it, all meaning to desist or leave off.
- (idiomatic, slang) An imperative used as a warning to stop, hide, or flee
1859, Sala, George Augustus Henry, “Strollers at Dumbledowndeary”, in Gaslight and Daylight, page 328:
- […] he holds earnest parley with some members of the upper gallery who are beguiling the time by pelting us with nut-shells, and broken pipes. Two or three 'hallos!' and 'now thens!' accompanied by a strong recommendation to 'cheese it' (i. e., act of cessation), cause these trifling annoyances to cease.
1908, O. Henry, The Voice of the City, page 154:
- The defence of Mr. Conover was so prompt and admirable that the conflict was protracted until the onlookers unselfishly gave the warning cry of "Cheese it—the cop!" The principals escaped easily by running through the nearest open doors into the communicating backyards at the rear of the houses.
1960, P. G. Wodehouse, Jeeves in the Offing, chapter VIII:
- Knowing that Bobbie would be on sentry-go made all the difference. Any gangster will tell you that the strain and anxiety of busting a safe are greatly diminished if you've a look-out man ready at any moment to say “Cheese it, the cops!”
a warning to stop, hide, or flee