The phrase curiosity killed the cat means that being inquisitive about other people’s affairs may get one into trouble.
The earlier form of the phrase was care killed a cat, in which care means disquiet. It is first recorded in Much adoe about Nothing (Quarto 1, 1600), by the English playwright and poet William Shakespeare (1564-1616); Claudio and Don Pedro are addressing Benedick:
– Don Pedro: As I am an honest man he lookes pale, art thou
sicke, or angry?
– Claudio: What, courage man: what though care kild a catte,
thou hast mettle enough in thee to kill care.
In Euery man in his Humor, first published in London in 1601, the English poet and playwright Benjamin ‘Ben’ Jonson (1572-1637) makes Cob use the phrase in a medley of exclamations successively expressing disordered haste, defiance of sorrow, aversion to worry, which is liable to kill even a cat, [uptails all is of obscure meaning], and a curse on the hangman:
He owes me fortie shillings (my wife lent him
out of her purse, by sixpence a time) besides his lodging,
I would I had it I shall haue it he saith next Action
Helter skelter, hang sorrow, care will kill a cat, vptailes all,
and a poxe on the hangman.
In Dictionary of Phrase and Fable (Philadelphia, 1898), the English clergyman and schoolmaster Ebenezer Cobham Brewer (1810-97) recorded the form care killed the cat only; according to him, the underlying image is that disquiet would exhaust the nine lives allotted to a cat—those nine lives were already proverbial in the mid-16th century [see footnote]:
Care killed the Cat. It is said that “a cat has nine lives,” yet care would wear them all out.
The earliest instance that I have found of the current form of the phrase is from an unsigned short story titled Aunt Hetty’s Stratagem, published in the Waterford Mirror and Tramore Visiter (Waterford, County Waterford, Ireland) of Wednesday 28th October 1868:
Often when I came home from a solitary ramble, I would find Aunt Hetty and Carrie in close conversation; and what caused my surprise, they became suddenly silent whenever I appeared. I was very curious to know the cause; I couldn’t help but suspect that it in some way concerned me.
‘Carrie,’ I said one day as we were taking our usual walk, ‘do you know you have begun to make me jealous? It seems to me Aunt Hetty takes you a great deal into her confidence. She never thinks of confiding in me so!’
‘Am I,’ said Carrie, laughing merrily. ‘I am sorry; but you will know by-and-by what Aunty Willis and I have so much to talk of.’
‘Very well,’ I said, laughing. ‘They say curiosity killed a cat once, so I will take warning and let things remain as they are.’
The second-earliest instance that I have found is from A Kitten’s Perplexity, published in The Neenah Daily Times (Neenah, Wisconsin) of Tuesday 23rd October 1883. In this story, a pet kitten, owned by some children, sees its own image reflected in a mirror and mistakes it for an actual cat; the kitten bangs its head against the mirror when it tries to make contact with its reflection, and finally withdraws to the solitude of the cellar:
During the remainder of the day it kept away from the living rooms of the house, and when taken its usual meal of bread and milk it left the dish untasted. The shock to the kitten has had altogether such bad effects that its little playmates manifest much concern lest its queerness be the precursor of its death, and additional testimony thus be given of the plausible proposition that curiosity killed a cat.
Note: In A Dialogue Conteinyng the Nomber in Effect of all the Prouerbes in the Englishe Tongue (London, 1546), the English playwright and epigrammatist John Heywood (circa 1496-circa 1578) wrote:
A woman hath nyne lyues lyke a cat.