postiche

1. Something false; a sham.
2. A small hairpiece; a toupee.

[French, from Italian posticcio, from posto, added (from Latin positus, past participle of pōnere, to place) or from Vulgar Latin *appostīcius (alteration of Latin appositus, past participle of appōnere, to place by, to add : ad-, ad- + pōnere, to place).]

Superadded; done after the work is finished, esp. when superfluous, inappropriate, or in poor taste.

The noun has 2 meanings:

Meaning #1: a covering or bunch of human or artificial hair used for disguise or adornment
  Synonyms: hairpiece, false hair

Meaning #2: something that is a counterfeit; not what it seems to be
  Synonyms: fake, sham