I have encountered the phrase "you're a caution" in a movie in a suggestive, possibly judgmental context. How is this to be understood and where does it come from?
J. E. Lighter, Random House Historical Dictionary of American English (1994), has this entry for caution:
caution n. a thing or (now esp.) a person that causes astonishment, annoyance, or amusement—also constr. with ref. to assorted animals. Now colloq.
Many of the nineteenth-century examples reported in this dictionary appear as part of a longer phrase, "a caution to X." For example, "The way I'll lick you will be a caution to the balance of your family" (1834); "The way I did sail was a caution to turkles and all other slow varmints" (1845); "The way that gal squealed ... was a caution to screech owls" (1861); "He began to scull himself along at a rate that was a caution to snakes" (1896); and "Ain't that a caution to yaller snakes?" (1899).
On the other hand, the colloquial use of "caution" didn't always have an identified recipient. For example, "The way in which the icy blast would come down from the bleak shore of the lake 'was a caution'" (1835); and "The way they pulled hair and cuffed ears was a caution" (1837).
John Bartlett, Dictionary of Americanisms (1848) includes an entry for "to be a caution" that includes numerous examples:
TO BE A CAUTION. To be a warning. A common expression used in familiar language.
[Example:] The way the Repealers were used up, was a caution to the trinity of O'Connell, Repeal, and Anti-Slavery, when they attempt to interfere with true American citizens.—New York Herald
[Example:] There's a plaguy sight of folks in America, Major, and the way they swallow down the cheap books is a caution to old rags and paper-makers.—Maj. Downing, May-day in New York
[Example:] A large portion of Capt. Marryatt's "Travels of Mons. Violet," is stolen from the New Orleans Picayune ; and it will not be surprising if Kendall [the author] lets his sting into this trans-Atlantic robber. He can do it in a way that will be a caution.
[Other examples omitted.]
The fourth edition of Bartlett, Dictionary of Americanisms (1877) adds a note at the end that "Caution to Snakes is often heard," but otherwise alters the entry for "to be a caution" very little.
John Farmer, Americanisms—Old and New (1889) suggests that at that date "a caution to snakes" may have been the standard phrasing:
CAUTION.—A CAUTION TO SNAKES, i.e., a warning. The expression is purely slang, and anything that causes surprise, wonder, fear, or indeed any unusual sensation, or anything out of the common, seems, in the vulgar tongue, to be "a caution" to this, that, and the other. To be a caution to snakes, however, bears the palm. [Examples omitted.]
At some point in the past century, however, the snakes went away, leaving the expression "isn't he [or she or it] a caution?" open-ended.
My mother was southern and used to say, "you're a caution to the buzzards," often followed by "you know that?" It was definitely a compliment. It meant your talents, charms, charisma - whatever struck her as pleasing at that moment - was so pleasing that you were a danger to others who, perhaps, might fall under your spell.
It's possible nobody will ever see this, but here it is
My grandmother used to say, "Isn't that a caution?" I was very young, but took it to mean, "an unusual or unexplainable happening" ... like a tire was flat for no apparent reason, something was missing, or someone did something strange.
I believe, the OED def. above is accurate, if you can interpret it's meaning.
Today's equivalent, might be "WTF?"