The noun marrowsky, which has also been spelt Marouski, Marowsky, morowski and mowrowsky, denotes a variety of slang, or a slip in speaking, characterised by the transposition of the initial letters or syllables of two words. The more usual term is spoonerism (cf. also malapropism and eggcorn).

The word is first recorded in the verbal form Marrowskying in the critical review of the first edition (1859) of A Dictionary of Modern Slang, Cant, and Vulgar Words, by the English publisher and author John Camden Hotten (1832-73), review published in The Athenæum: Journal of Literature, Science, and the Fine Arts (London) of 23^rd July 1859:

“One old English mode of canting [to quote our author] was the inserting of a consonant betwixt each syllable; thus, taking g, ‘How do you do,’ would be ‘Howg dog youg dog?’ This, according to Grose¹, was called gibberish.”
Another cant, we may add, has recently been attempted by transposing the initial letters of words; so that a mutton chop becomes a cutton mop, a pint of stout a stint of pout; but we are happy to add that it has gained no ground. This was called Marrowskying.

(¹ the English antiquary and lexicographer Francis Grose (1731-91), author of A Classical Dictionary of the Vulgar Tongue (first edition published in 1785))

Hotten must have taken this into consideration since, in the second edition (1860), he elaborated on what the reviewer had written:

Another Cant has recently been attempted by transposing the initial letters of words, so that a mutton chop becomes a cutton mop, a pint of stout a stint of pout; but it is satisfactory to know that it has gained no ground. This is called Marrowskying, or Medical Greek², from its use by medical students at the hospitals. Albert Smith terms it the Gower-street Dialect.

(² cf. it’s Greek to me)

In the same edition, Hotten thus defined medical Greek:

The slang used by medical students at the hospitals. At the London University they have a way of disguising English, described by Albert Smith as the ‘Gower-street Dialect,’ which consists in transposing the initials of words, e.g., “poke a smipe,”—smoke a pipe, “flutter by”—butterfly, &c. This disagreeable nonsense is often termed Marrowskying.

Hotten was referring to The adventures of Mr. Ledbury and his friend, Jack Johnson, by the English author Albert Smith (1816-60), first published in Bentley’s Miscellany (London) in 1843; Jack Johnson has just met a medical student:

“Will you poke a smipe, Mr. Johnson?” asked Mr. Prodgers.
“Will I do what?” returned Jack. “Upon my honour, I do not quite comprehend you.”
“Oh! I forgot,” replied Mr. Prodgers. “Cart before the horse, you know; poke a smipe—smoke a pipe, and so on: nothing else. Medical Greek, Gower Street dialect. We think it rather a fine language.”

The word marrowsky is of unknown origin. It might be from a personal name. A correspondent gave the following explanation in The Irish Times of Tuesday 25^th September 1923:

“MARROWSKYING.”
To the Editor of The Irish Times.

Sir,—The letter of “S.” which appeared this morning in your columns reminds me that in my childhood, many years ago, an old cousin used to entertain me with what we now call “Spoonerisms,” but which she termed “Morowskis.” On my inquiring the reason for this curious name my cousin told me that her mother (who dated from the eighteenth century) had taught her the game, stating that the original perpetrator of these strange transpositions was a Polish Count who was well known in London society of that period.—Yours, etc. “E. D-N.”
                                                                                         Dun Laoghaire, September 24^th, 1923.

The author of this letter refers to Józef Boruwłaski (1739-1837), a Polish musician who toured in several European countries, among which the United Kingdom, but no evidence supports the theory that he was “the original perpetrator of these strange transpositions”.

An article titled Mr. Gladstone’s secret slang, published in The Manchester Courier, and Lancashire General Advertiser of 28^th January 1893, contains:

The Premier³ has, in the course of his philological studies, given much attention to “slang.” We do not say that he talks the cuse-cat of the Hottentots, though he may know something of the gergo of the Neapolitans. He doubtless is acquainted with French argot, can “patter” schelta with a tinker, talk “back slang” with the skill of Albert Chevalier, or marrowskying with a medical student. A scholar so thoroughly “up to date” is Mr. Gladstone that he rightly regards slang as “the shorthand of speech,” and he by no means disdains to use a “flash,” “cant,” “vagrant,” or “fugitive” word when it is more expressive and has more “grip” than what is generally called “the Queen’s English,” though it might be asserted that even her Majesty has, in written or spoken language, given the Hall mark of her approval to an Americanism, or some terse expression which might be called “slang.”

(³ William Ewart Gladstone (1809-98): Prime Minister 1868-74, 1880-85, 1886, and 1892-94)

The following was published in The British Medical Journal of 22^nd June 1912:

THE PSYCHOLOGY OF “MARROWSKYING.”

All actors live in dread of “marrowskying,” that curious transposition of syllables which often illustrates the truth of the saying that from the sublime to the ridiculous there is but a step. The actor who said, “Stand back, my lord, and let the parson cough” (instead of “coffin pass”) may have made a solitary slip, but in some persons “marrowskying” amounts to a veritable infirmity. We knew an excellent clergyman who was the delight of the more frivolous among his hearers because he was never known to preach a sermon without introducing a reference to a “farren big tree,” or dwelling on the fact that “many are called but chew are fosen,” ending the text with the impressing exhortation, “Be ye therefore of the fosen chew.” We remember a fastidious lady shocking the porter at a railway station by telling him that she had only a “rag and a bug,” meaning, of course, a rug and a bag. The name of the head of a famous college at Oxford⁴ has become proverbial for this kind of defect of speech. How does this kind of inversion arise? Professor Joseph Jastrow, the well-known American psychologist, says it is due to an “intrusion of the subconsciousness” of the speaker. We subconsciously construct our sentences before uttering them, and sometimes the preliminary framework gets mixed up with the permanent timber. According to the Literary Digest, Professor Jastrow says: “The complexity of speech requires the occupation with many processes at once, and some of these—the nicer, more delicate, less familiar ones—will receive the major attention, while the routine factors engage but a minor degree of concern. Slight fluctuations in the condition of the speaker—physiological ones, such as fatigue, and, for the most part, psychological ones, such as excitement, apprehension, embarrassment—will induce variations in the nicety of adjustment that are recognizable as typical slips of tongue or pen, and, still more significantly, of the tongue-and-pen-guiding mechanism. . . . There are the anticipations, the persistencies, the interchanges, the substitutions and the entanglements of letters, and of words and parts of words, and of phrases—all of them indicative of shortcomings in the minute distribution of attention and co-ordination.” He gives a number of examples, and shows that “marrowskying” is not confined to the tongue, but occurs in writing. This is one of the many sources of error in copying printed or manuscript matter. The mind runs on ahead of the eye, and a jumble of syllables is the result. Should this by any chance happen to make sense, it leads to a corruption of the text which may have far-reaching consequences. Copyists’ errors have been classified; it would be interesting if “marrowskyers’” blunders could also be classified and the etiology and mechanism of the condition elucidated. The occurrence of an accident of the kind engenders a fear of repetition of the misadventure, which may lead a man to give up all attempts at public speaking.

(⁴ The Reverend William Archibald Spooner (1844-1930) has been credited with many spoonerisms, although he probably made one only. In fact, legend has it that it was he who told a “porter at a railway station” that he “had only a rag and a bug”.)