My son marched in from borrowing my car the other day. “What is that CD you’ve been listening to?” he said. Bracing myself for the usual burst of cross-generational scorn, I explained that it was Decade, a compilation of early Neil Young material. “It’s … quality!” he enthused. Or rather, “quali ’y”: the glottal stop is compulsory.I tell this story not for its surprise value – who can predict what the young are going to think about anything, let alone whiny Canadian singer-songwriters – but as an example of the changing role of the word “quality”. The OED has about 5,000 words on the use of “quality” as a noun; precisely 84 on its use as an adjective, and none at