Jiggers, the cops! Reader Paul Fralick recalls that warning cry from decades ago, "in association with road hockey games and having to scatter when we saw the blue Toronto police cars coming down the street. But I am sure the phrase is much older, perhaps going back to the twenties or thirties."
Nobody is certain of its origin, but any number of meanings of jig and jigger may have contributed to the phrase, including jigger (or chigger) as an annoying flea and jigger (or gigger) as the 19th-century word for a jail or jail cell. Perhaps the word was chosen simply for its urgent sound.
What we do know is that jiggers, jigger and jiggeroo have been around in this sense at least since 1911 when, according to a reference book cited in the Oxford English Dictionary, the word jigger meant "look out; be careful. 'Jigger, kids, the teacher's coming.' " A 1919 dictionary described jiggeroo as "hobo cant" and compared it with "cheese it," a similar alert: Cheese it, the cops! In Zounds!: A Browser's Dictionary of Interjections, Mark Dunn suggests "cheese it" was "probably an early 19th-century mispronunciation of 'cease it.' " ( Zounds! is illustrated by Mad magazine's Sergio Aragones, an achievement that doesn't quite scale the heights of Margaret Ernst's landing James Thurber to illustrate her 1939 word book In a Word, but isn't to be sneezed at.) A 1972 dictionary of prison slang defined a jigger as a lookout man, someone who would watch for the authorities and send a message by relay if they approached.
There might be some connection to the earlier expression "well, I'll be jiggered," which has served as a mild, unobjectionable oath since at least the 19th century. Charles Dickens used it in Great Expectations in 1861: " 'Well, then,' said he, 'I'm jiggered if I don't see you home.' " Again, it is not clear where this jigger came from. The main bet is that it's a corruption of the flea mentioned above - the West Indian chigoe, a tiny creature whose burrowing into people's feet causes all sorts of problems. But if you care to place a side bet, it may derive from the jigger as jail.
Among the many other senses of jigger is the tiny shot glass used for measuring whisky (probably from the small size of the flea) and the tackle used for a style of fishing, jigging, that involves jerking a hook or hooks. And one could spend the whole day studying the evolution of jig, which cropped up in the 1500s as a dance and as a mocking ballad. By the end of the century it referred as well to a practical joke or scam, as in Thomas Nashe's 1592 work Pierce Penilesse: "Let not your shops be infected with anie such goose gyblets or stinking garbadge, as the Iygs of newcomers." It is from the sense of the jig as trick that we get the expression "the jig is up" - the ruse has been discovered, the game is over, we've been rumbled. Jiggers, the cops! This notion of subterfuge reappears in jiggery-pokery - a bit of underhanded business - from the Scottish phrase joukery-pawkery, a play on the Scottish noun joukery, for trickery, which in turn derives from the Scottish verb jouk, meaning to twist one's body to duck a blow or evade an arrow. Using physical ingenuity to escape death would seem less a trick than an admirable achievement, but I suppose it depends on which party in the battle you're supporting.
If you tire of using jiggers as an interjection, you might give a thought to jeepers, which, as Dunn notes, is one of an infinite number of euphemisms for the blasphemous oath Jesus Christ. Otherwise, you could review sidekick Robin's inventive oaths during the 1960s television series Batman, usually beginning with "holy," or mine similar oaths uttered in The Adventures of Aquaman by the hero's sidekick, Aqualad. The one that springs to mind is, "Jumping porcupine fish!" No word on whether those fish respond to jigging.