The dialectologist Elizabeth Wright described the boggart as 'a generic name for an apparition';[1] folklorist Simon Young defines it as 'any ambivalent or evil solitary supernatural spirit'.

[2] Halifax folklorist Kai Roberts states that boggart ‘might have been used to refer to anything from a hilltop hobgoblin to a household faerie, from a headless apparition to a proto-typical poltergeist’.

[6] Boggart is written in many different forms: "boggard" (particularly in Yorkshire), "baggard", "bogerd", "boggat", "bogard", "boggerd", "boggert", "bugart", "buggard", and "buggart".

This also makes boggart a close linguistic cousin of "bogle" (or boggle, a Scots variant), 'bugaboo', "bugbear", "bug", "bogeyman" and "bogie", all of which also derive from bugge.

T. Sternberg's 1851 book Dialect and Folk-lore of Northhamptonshire describes a certain boggart as "a squat hairy man, strong as a six year old horse, and with arms almost as long as tacklepoles".

The "Boggart of Longar Hede" from Yorkshire was said to be a fearsome creature the size of a calf, with long shaggy hair and eyes like saucers.

[14] The boggarts of Lancashire were said to have a leader, or master, called 'Owd Hob', who had the form of a satyr or archetypical devil: horns, cloven hooves and a tail.

[15] The name of at least one Lancashire boggart was recorded, "Nut-Nan", who flitted with a shrill scream among hazel bushes in Moston near Manchester.

[16] In Yorkshire, boggarts also inhabit outdoor locations, one is said to haunt Cave Ha, a limestone cavern at Giggleswick near Settle.

A farmer's wife, the old couple claimed, just two weeks earlier had heard doors banging in her farmhouse at night, then loud laughter; she looked out to see three candles casting blue light and a creature with red burning eyes leaping about.

But distribution maps show that "Boggartdom" (the area in which stories of boggarts are found) extended to northern Cheshire, much of Derbyshire, northern Lincolnshire, the old West Riding of Yorkshire, parts of the North Riding, the fringes of Westmorland, and perhaps Nottinghamshire, and possibly, at one time, as far north as Cleveland and as far south as Skegness.

Most famously there is a large municipal park called Boggart Hole Clough, which is bordered by Moston and Blackley in Manchester.

Legend has it that these potholes are the dwelling place of grotesque flesh-eating boggarts whose angry growls have allegedly been heard reverberating from the depths of the dark caverns beneath (hence the name).

Boggard Lane, between the villages of Oughtibridge and Worrall in South Yorkshire, is generally believed to derive from the term "boggart".

In 2019 folklorist Simon Young launched a survey to test modern understandings of the word 'boggart' in England and particularly Lancashire, Cheshire, Derbyshire and Yorkshire.

The boggarts in J. K. Rowling's Harry Potter are shape-shifters whose true form is unknown, that change shape to resemble their beholder's worst fear (possibly inspired by the "clutterbumph" in Paul Gallico's Manxmouse).

[27] In the 2014 fantasy film Seventh Son an enormous malevolent boggart attacks the protagonists while they are on their journey to find the antagonist character.

[32] In 1882, the weekly journal All the Year Round, then edited by Charles Dickens Jr., describes a marsh-dwelling boggart, who milked farmers' cows at night.