The unreadable book.

It is always the unreadable that occurs. —Oscar Wilde, The Decay of Lying

People toss around the word unreadablea lot—invariably about something they have, by definition, read, at least in part. By “people,” I specifically mean people who read for a living, or part of it. It’s one of those conversation enders, a condemnation so sweeping and damning that one is powerless to argue.

But beyond this, unreadablecan mean many things. An unreadablebook may be pretentious, obscure, indecipherable, and/or not worth the time it takes to decode. Occasionally, the unreadable text takes vague inspiration from modernism, postmodernism, and academic writing. Footnotes are not uncommon. This form—aspirational unreadability—is popular among the very young and the mentally ill.

There is writing so incompetent that it is unreadable: clunky sentences, random tense shifts, leaden dialog. This is particularly irritating in the case of plot-driven narrative, with a special emphasis on mysteries. Terrible translations also belong in this category, although they are sort of a category of their own.

Then there is theliterallyunreadable, otherwise known as the illegible. Granted, this is not as common in a post–typewriter ribbon age. But weird fonts, the use of symbols, and computer viruses can all contribute to unreadability. Handwritten manuscripts are often unreadable, too—although it should be said that in my experience, these usually fall into one of the above categories, too.

To be unreadable means that the book in question is not merely bad but offensivelybad, an imposition on one’s valuable time. It is not pleasurable or instructive in any way. An unreadable book serves none of the functions of a book, whatever that may mean to an individual. The epithet is high-handed and subjective. Anyone who uses it is redefining literacy! At least for a moment.

Sadie Stein is contributing editor of The Paris Reviewand the Daily’s correspondent.