Merriam-Webster

A groom in livery.

Additionally…

In novels, you may read a tiger as the servant who rides in the back of a curricle and takes the reins after his master exits.

Merriam-Webster

An impressive, pompous, or fashionable air or display : a person dressed in the height of fashion : a person of high social position or outstanding competence

1811 Vulgar Tongue

A gentleman. A well-dressed map. The flashman bounced the swell of all his blunt; the girl’s bully frightened the gentleman out of all his money.

One returned from the East Indies with but a moderate fortune of fifty or sixty thousand pounds, a diminutive nabob: a term borrowed from the chicken turtle.

–From the 1811 Dictionary of the Vulgar Tongue.

I keep wanting to say kebab when I see this…

Merriam-Webster

A person of great wealth or prominence

Wikipedia

…can also be used metaphorically for people who have a grandiose style or manner…

Free Dictionary

One who returns to Europe from the East with immense riches: hence, any man of great wealth. “A bilious old nabob.” –Macaulay.

A man kept by a lady for secret services.

–From the 1811 Dictionary of the Vulgar Tongue.

Not sure the term “secret services” is so secret…

1811 Vulgar Tongue

A riotous disorderly fellow.

Merriam-Webster

A showy foppish man : rake

*Interesting definition combo — fop and rake together? Not in my romance.

Merriam-Webster

A rude ill-bred person : a stingy morose person

Wikipedia

A boorish person; a peasant

1811 Vulgar Tongue

Originally, a labourer or husbandman: figuratively a rude, surly, boorish fellow. To put a churl upon a gentleman; to drink malt liquor immediately after having drunk wine.

A man, a fellow, a rogue. The cove was bit; the rogue was outwitted. The cove has bit the cole; the rogue has got the money.

–From the 1811 Dictionary of the Vulgar Tongue.

The heroine may call the hero a blackguard at first, but in the end only the villain fits the description.

Merriam-Webster

A rude or unscrupulous person : a person who uses foul or abusive language

Wiktionary

A vulgar and uncouth person. One who has a less than trustworthy level of inhibition.

1811 Vulgar Tongue

Black guard — A shabby, mean fellow; a term said to be derived from a number of dirty, tattered roguish boys, who attended at the Horse Guards, and Parade in St. James’s Park, to black the boots and shoes of the soldiers, or to do any other dirty offices. These, from their constant attendance about the time of guard mounting, were nick-named the black-guards.

Another fun, foppy term, but with more history.

1811 Vulgar Tongue

Maccaroni (sic). An Italian paste made of flour and eggs. Also a fop: which name arose from a club, called the Maccaroni Club, instituted by some of the most dressy travelled gentlemen about town, who led the fashions; whence a man foppishly dressed, was supposed a member of that club, and by contraction styled a Maccaroni.

Merriam-Webster

A member of a class of traveled young Englishmen of the late 18th and early 19th centuries who affected foreign ways b : an affected young man : FOP

Wikipedia

In 18th century England, a macaroni was a fashionable man who dressed and even spoke in an outlandishly affected manner. The term pejoratively referred to a person who exceeded the ordinary bounds of fashion in terms of clothes, eating and gambling. Young men who had been to Italy on the Grand Tour adopted the Italian word and said that anything that was fashionable or à la mode was ‘very macaroni’. The expression was particularly used to characterize those people who dressed in high fashion 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. Macaronies combined the enjoyment of wine, sex and song with effeminacy of dress. They are a precursor to the dandy.
The song Yankee Doodle from the time of the American Revolutionary War talks of a man who stuck a feather in his hat and called it Macaroni. This shows that “Macaroni” at the time was a slang term for the most up-to-date of fashions.