The noun Micawberism denotes irresponsible or unfounded optimism, often as a habitual attitude.

This noun occurs, for example, in the following from Ever-higher mortgage rates will leave Rishi Sunak feeling low, by Heather Stewart, published in The Guardian (London and Manchester, England) of Friday 23^rd June 2023:

Some at Westminster have questioned whether Sunak’s plan to wait until late 2024 for an election looks quite such a good bet now that rates are expected to remain higher for much longer than previously thought.
But the elections expert Rob Ford, speaking for the academic network UK in a Changing Europe, said the prime minister was likely to continue to wait in the hope that things may change for the better or fresh events overtake the current crisis.
“Micawberism and wishful thinking are incredibly powerful forces—and the more unpleasant the outcome you’re facing, the stronger they tend to become,” he said. “The belief that something might turn up to make these things go away will be a hard one for these people to shake.

The noun Micawberism refers to Wilkins Micawber, a character in The Personal History of David Copperfield (London: Bradbury & Evans, 1850 ¹), by the English novelist Charles Dickens (1812-1870). In this novel, Wilkins Micawber’s unquenchable optimism is characterised by his frequently stated belief that something will ‘turn up’.

¹ The Personal History of David Copperfield was first published as a serial in 1849 and 1850.

It was perhaps Charles Dickens himself who coined Micawberism, since the earliest occurrence of this noun that I have found is from Curious Misprint in the Edinburgh Review, published in Household Words. A Weekly Journal. Conducted by Charles Dickens (London, England) of Saturday 1^st August 1857.

—Context: An anonymous reviewer had written the following in The License of Modern Novelists, published in The Edinburgh Review, Or Critical Journal (Edinburgh, Midlothian, Scotland) of July 1857:

Even the catastrophe in ‘Little Dorrit’ is evidently borrowed from the recent fall of houses in Tottenham Court Road, which happens to have appeared in the newspapers at a convenient period.

—Charles Dickens responded as follows in Curious Misprint in the Edinburgh Review, published in Household Words of 1^st August 1857:

If the Editor of the Edinburgh Review (unbending from the severe official duties of a blameless branch of the Circumlocution Office) had happened to condescend to cast his eye on the passage, and had referred even its mechanical probabilities and improbabilities to his publishers, those experienced gentlemen must have warned him that he was getting into danger; must have told him that on a comparison of dates, and with a reference to the number printed of Little Dorrit, with that very incident illustrated, and to the date of the publication of the completed book in a volume, they hardly perceived how Mr. Dickens could have waited, with such a desperate Micawberism, for a fall of houses in Tottenham Court Road, to get him out of his difficulties, and yet could have come up to time with the needful punctuality.

Very early, the name Micawber came to designate a person likened to Wilkins Micawber as being a romantic, irresponsible or feckless optimist.

The earliest generic uses of the name Micawber that I have found are as follows, in chronological order:

1-: From the title given to the following paragraph, from The Scotsman: Or Edinburgh Political and Literary Journal (Edinburgh, Midlothian, Scotland) of Saturday 24^th November 1849:

The Political Micawber.—The Morning Chronicle says happily—“In spite of his defiant eye and petulant tongue, we greatly fear that the affairs of Mr Disraeli, like those of Mr Micawber, are coming to a crisis.” ²

² This quotation is from The Morning Chronicle (London, England) of Tuesday 20^th November 1849.

2-: From Palace-yard Politics, a parliamentary correspondence from London, published in The Nation (Dublin, County Dublin, Ireland) of Saturday 9^th March 1850:

Mr. George Smythe, who speaks Chartism at Canterbury, and writes Austrianism in the Morning Chronicle, and who last year voted for Mr. Hume, records no opinion in 1845; the “historic fancy” having, perhaps, come over him, that neither extreme answers and that, with true Micawber philosophy, it is better to wait until something “turns up.”

3-: From the review of Our County (London: Henry Colburn, 1850), a novel by John Mills (1815-1887)—review published in The Weekly Chronicle (London, England) of Sunday 25^th August 1850:

The lawyer at length appears in his real character—that of a warm and devoted friend of the Warrens. It turns out that having long before discovered that the family estates were hopelessly committed to the power of the Rackets, he had resolved to play the fox in the affair, with the hope that, according to Micawber philosophy, “something would turn up” in the baronet’s favour; and that he therefore pretended to ally himself with the Rackets, of which well-meant, but rather overdone game of double-shuffle, his sanction of the addresses of young Racket to his daughter formed a part.

4-: From Jackson’s Oxford Journal (Oxford, Oxfordshire, England) of Saturday 7^th September 1850:

ABINGDON.

Impudent Attempt at Swindling.—On Saturday evening last, a traveller in the “Jeremy Diddler” ³ line, came to the Crown and Thistle Hotel, in this town, and with a passing observation on his lack of luggage, which, he remarked, was left at Oxford, ordered supper and a bed, both of which he enjoyed. On Sunday morning he breakfasted, and coolly ordering dinner, proposed to himself a walk, to “call on a friend in the neighbourhood;” this, however, could not be allowed by Mr. Lindars, whose organs of suspicion were aroused, without a walking accompaniment of a waiter, who started, taking to himself the companionship of a stout cudgel. The traveller finding he was followed, returned to the inn, but by no means to his ease, for, from the “close taxation” of our friend Lindars, he was compelled to confess himself, Micawber like, “without adequate means of remuneration.” At last, he left, and, arriving at the Bear, at Wantage, repeated the same trick, but circumstances there appearing sadly against him, Mr. W. Harris Rawson (for such was his travelling name), was taken before Thomas Goodlake, Esq., who, without regard to his protestations, committed him as a vagrant for seven days to the house of correction, at Abingdon; the most impudent part of the story remains to be told. On the policeman who brought him to Abingdon, pulling up at an inn in Ock-street, his prisoner, with the air of a Regent-street lounger, said, “Drive on to the Crown and Thistle; that is my hotel.”

³ Jeremy Diddler designates a mean swindler or cheat. This refers to the chief character in Raising the Wind (1803), a farce by the British playwright James Kenney (1780-1849).

Interestingly, an early allusion to what has become known as the Micawber Principle occurs in the following from What is to be done for the farmer, published in The Inverness Courier, and General Advertiser (Inverness, Inverness-shire, Scotland) of Thursday 27^th December 1849:

If an excellent low-lying farm of 464 Scotch acres, skilfully farmed, places the tenant only one step beyond ruin—if the value of a fat cow would turn the scale—if the death of a horse would put the farmer in the miserable position (according to Micawber) of the man who spends 6d. a year beyond his annual income, it proves the necessity of some general measures of relief.

This refers to the following piece of advice that Wilkins Micawber gives to David Copperfield:

“Annual income twenty pounds, annual expenditure nineteen nineteen six, result happiness. Annual income twenty pounds, annual expenditure twenty pounds ought and six, result misery.”