Adjectives used to describe sound quality often mean nothing more than what the user prefers them to imply. Some use "warm" to mean a rolled off top end while others want to suggest a full, rich midrange and others might even mean a "laid back" sound when they use "warm" to describe what they are hearing.
Descriptive words used in the context of audio reviews came about mostly through the efforts of J. Gordon Holt at Stereophile. Harry Pearson with The Absolute Sound added to the vocabulary and other reviewers have joined in with words that mean as much to them as anyone else. Reading reviewers more than a few times will generally give you the best idea of how a particular writer intends their words to be understood.
For now, here's J.G. Holt's glossary; http://www.stereophile.com/reference/50/index.html
You can also place "audio glossary" in any search engine and find several other versions with often unique interpretations to each word.
