definition: used after 1764 to mean “fop, dandy” because it was an exotic dish at a time when certain young men who had traveled the continent were affecting French and Italian fashions and accents. There is said to have been a Macaroni Club in Britain, which was the immediate source of the term.

from: Online Etymological Dictionary

definition: a coxcomb. The word is derived from the Macaroni Club, instituted by a set of flashy men who had travelled in Italy, and introduced Italian maccheroni at Almack’s subscription tables. The Macaronis were the most exquisite fops that ever disgraced the name of man; vicious, insolent, fond of gambling, drinking, and duelling, they were (about 1773) the curse of Vauxhall Gardens.

»We are indebted to the Macaronis for only two things: the one is the introduction of that excellent dish…macaroni, and the other is the invention of that useful slang word ‘bore’ (boar), which originally meant any opponent of dandyism.« Cassell’s Magazine: London Legends.

from: Dictionary of Phrase and Fable (1898)

the fashion of the macaronis was too much of everything: they dressed with stripes and tall, powdered wigs with a little hat on top which was so high that it could only be removed on the point of a sword. more reading on wikipedia

In 1772 dandyism became again paramount. A band of young bloods returned from an extended tour abroad, and while in Italy they had contrived to get several new ideas about dress into their somewhat empty heads. Fired with an ever growing sense of their own importance as arbiters of fashion, they formed themselves into a group known as the Macaroni Club, in contradiction to the good-fashioned Beef Steak Club of London.

The Macaronies dressed their hair in enormous side curls, with a hideous knocker-like twist at the backs. With this exaggerated coiffure a tiny hat was worn, which it was correct for the wearer to raise with his tasselled cane. A soft white handkerchief was tied in a huge bow under the Macaroni’s chin; his coat was short, and his tight knee breeches were made of striped or flowered silk. Thus garbed, with innumerable dangling seals, two watches at least, silk stockings, and diamond-buckled shoes, the dandy walked abroad, eminently satisfied with himself, and quite convinced that his appearance was greatly envied.

from: Roger Boutet de Monvel: Beau Brummell and His Times. With a Chapter on Dress and the Dandies by Mary Craven. London, 1908: 17f.

Puppy macaronies are such professed admirers of themselves that they pay all their adoration to the looking glass, their sweet persons, let “them be ever so ugly, are their chief delight, they think of nothing else. Their origin we must not trace ; as, commonly, a hairdresser was their father, or by means of a dancing-master they bopped into the world.

from: Freemason’s Magazine, Or General and Complete Library (July 1795)