Ultracrepidarian is an adjective noting or pertaining to a person who criticizes, judges, or gives advice outside the area of his or her expertise. You probably know them, and if you do not, count your many blessings.
One might think that ultracrepidarianism was a concept invented for the 21st century, with people magically being able to espouse wisdom about everything on the Internet.
In fact, the term “was first publicly recorded in 1819 by the essayist William Hazlitt in an open Letter to William Gifford, the editor of the Quarterly Review: ‘You have been well called an Ultra-Crepidarian critic.’ It was used again four years later in 1823, in the satire by Hazlitt’s friend Leigh Hunt, Ultra-Crepidarius: a Satire on William Gifford.”
And roots are much older than that. Ultracrepidarianism “draws from a famous comment purportedly made by Apelles, a famous Greek artist [of the 4th century BC], to a shoemaker who presumed to criticise his painting.” The Latin phrase ‘Sutor, ne ultra crepidam’, was set down by Pliny [the Elder, 1st century A.D.] and later altered by other Latin writers to ‘Ne ultra crepidam judicaret.’ [It] can be taken to mean that a shoemaker ought not to judge beyond his own soles.”
Thus, the sign of well-trained healthcare professionals, for example, is that if something falls outside their field of expertise, they find the person who knows, not pretend to have an answer.
Still, there was a series of ads from Holiday Inn Express who handle the notion of giving advice outside the area of one’s expertise, which are mildly humorous, involving a helicopter pilot, a nuclear reactor scientist, a surgeon and a rapper, plus several others.