But I hasten to point out that nouns can be used as modifiers of other nouns....that does not make them adjectives! Examples are chicken soup, hospital bed, and library book.
How's THAT for pedantic!
Well played! But I was talking about the fact that "quality" as a noun can't be properly used to modify "instruction" rather than a blanket statement that nouns can't be used to modify other nouns.
Though, technically speaking, if you want to get pedantic we can get into the subtle but important differences between a "noun" a "noun modifier" and an "adjective" - perhaps over a California Cabernet or an ice-cold beer? (See what I did there?)
---------- Post added July 4th, 2015 at 03:55 PM ----------
Ah, but language arises from a people who use it. Dictionaries may try to codify term.s & usage, but if a large people group use a word in a particular way that conveys a universally accepted meaning, by what source are they overruled? What makes them 'wrong?'
Strunk & White's "The Elements of Style"
The American Heritage Book of English Usage
The Chicago Manual of Style
The New York Times Manual of Style and Usage
The AMA Manual Of Style
The Associated Press Stylebook
Lynch's "Guide To Grammar & Usage"
Publication Manual of The APA
The Business Style Handbook
The Gregg Reference Manual
The MLA Handbook For Writers
The CSE Manual For Authors, Editors, and Publishers
That's off the top of my head, for American English. There are more, and they all have their counterparts for British, Canadian, and Australian English as well.