classical music. In technical musical usage this means music composed during the late eighteenth and early nineteenth centuries, characterized by the development of the sonata by such composers as Mozart. In popular use, however, the term is used to mean any serious art music as distinct from jazz, pop, or folk.
The definition of vague is something unclear, hazy or uncertain. An example of vague would be directions to a house that don't include street names. YourDictionary definition and usage example.
1706, probably a back-formation of hazy. Sense of confusion, vagueness is 1797. The English differentiation of haze, mist, fog (and other dialectal words) is unmatched in other tongues, where the same word generally covers all three and often cloud as well, and this may be seen as an effect of the English climate on the language.