fancypants

/F AE1 N S IY0 P AE0 N T S/
noun
  1. 1

    A person wearing fancy clothing; a member of a social elite.

  2. 2

    A person very concerned with their appearance.

Source: https://en.wiktionary.org/wiki/fancy%20pants, https://en.wiktionary.org/wiki/fancypants