Why did Antonin Scalia criticize Merriam-Webster’s definition of the word “modify” in a 1994 case?

In the 1994 case MCI Telecommunications Corp. v. American Telephone & Telegraph Co., Justice Antonin Scalia criticized Webster’s Third New International Dictionary for its definition of the word "modify."1

Scalia, a proponent of originalism, objected to the dictionary’s inclusion of a definition that allowed "modify" to mean making a "basic or important change." He argued that the word inherently connotes "increment or limitation" and that providing contradictory definitions—one for minor changes and one for fundamental changes—rendered the word meaningless. He characterized the inclusion of the "important change" definition as an "intentional distortion" or "careless or ignorant misuse" of the language.1

Merriam-Webster’s editor in chief, Fred Mish, defended the dictionary, noting that Webster’s Third was simply making explicit the various ways the word was used by reputable writers, such as T.S. Eliot. Mish argued that the dictionary’s descriptive approach accurately reflected usage, whereas Scalia’s criticism relied on stale, ill-founded objections to the dictionary's 1961 publication.1