An amusing list of Victorian slang from Passing English of the Victorian era, a dictionary of heterodox English, slang and phrase, 1909, by James Redding Ware (who, incidentally, under the pen name of Andrew Forrester, created one of the first fictional female detectives.)

I especially like Afternoonified: A society word meaning “smart”, e.g. “The goods are not ‘afternoonified’ enough for me.”

and Podsnappery: Wilful determination to ignore the objectionable or inconvenient, at the same time assuming airs of superior virtue and noble resignation.

Dipping into the Passing English dictionary:

Flapper, which I’d always thought of as a 1920s term, was in use as early as 1892 for “A very immoral young girl in her early ‘teens’.”

Flash dona: A high-class low-class lady (thieves’ word).

Gospel of Gloom: Satirical description of aestheticism which tended to doleful colours, gloomy houses, sad limp dresses, and solemn, earnest behaviour.
Were these Victorian goths?

Fit in the arm: A blow. In June 1897 one Tom Kelly was given into custody by a woman for striking her. His defence before the magistrate took the shape of the declaration that ‘a fit had seized him in the arm’, and for months afterwards back street frequenters called a blow a fit.

He worships his creator: Said of a self-made man who has a good opinion of himself.

Who took it out of you? Meaning wholly unknown to people not absolutely of lower class.

An interesting find– Deuce: Dusius–the erotic God of Nightmare, passing (15th century in England) into Robin Goodfellow.
The most familiar shape of Deuce is Robin Goodfellow, whose pictorial representation has long since been turned out of good society. If any curious reader is desirous of seeing him in his habit as he lived, he must be prepared to pay him five pounds for a copy of Mr Thomas Wright’s remarkable little book upon Phallic worship. Its study will enable him to comprehend Shakespeare’s allusions to this alarming personage–probably Robin Goodfiller.

The internet seems to have nothing on Robin Goodfiller outside of this dictionary. According to Wiktionary, dusius is “a kind of evil spirit”, from  Gaulish *dusios (“incubus, monster”), probably from Proto-Indo-European *dʰeus- (“spirit”). Compare Czech duše (“soul”).

Dusius exists today as an Italian folk/viking metal band.

And Whitechapel Warriors: Militia of the Aldgate district; and
White Army, The: A band of men who formed themselves together to combat social evil.
Was Victorian London adorned with roaming bands of vigilantes and do-gooders? The only other reference I can find to Whitechapel warriors is in a dialogue, Bon Gaultier and his Friends, in Tait’s Edinburgh Magazine, 1844. Bon Gaultier was a nom de plume of the writers William Edmondstoune Aytoun and Sir Theodore Martin, and their Whitechapel warriors seems to be an epithet for an invented regiment, the Ninth Poltroons, after whom we hear about “the Black Skulkers, a fine cavalry regiment, which made war principally upon its own account.” I may want to borrow them.
(I drift, but I’ll forget this if I don’t write it down — I read somewhere that the tradition of natty cavalry uniforms got started when mounted soldiers would raid the baggage trains and dress in what they seized. And now I can’t find the article again, chiz.)

As for the White Army (of London), I can’t find any other record of it.

A few more from The Art of Manliness, Manly Slang from the 19th Century:

Bully Trap: A brave man with a mild or effeminate appearance, by whom the bullies are frequently taken in.

Fart Catcher: A valet or footman, from his walking behind his master or mistress.

Gullyfluff: The waste — coagulated dust, crumbs, and hair — which accumulates imperceptibly in the pockets of schoolboys.

Half-mourning: To have a black eye from a blow. As distinguished from ” whole-mourning,” two black eyes.

Out of Print: Slang made use of by booksellers. In speaking of any person that is dead, they observe, “he is out of print.”

Tune the Old Cow Died Of: An epithet for any ill-played or discordant piece of music.