A young city or suburban resident with a well-paid professional job and an affluent lifestyle

The American Heritage® Dictionary of the English Language

or

a young upwardly mobile professional person; someone under 40 who prospered during the 1980s

WordNet ® 1.6, © 1997 Princeton University

the following link would hopefully clear the vagueness around the term.
http://www.wikipedia.org/wiki/Yuppie_Philosophy
in contrast, the hippie is well defined here:
http://www.wikipedia.org/wiki/Hippie

YUPPPIES ARE NOT HIPPIES!!!!!