WordNet (r) 3.0 (2006):

ersatz
    adj 1: artificial and inferior; "ersatz coffee"; "substitute
           coffee" [syn: ersatz, substitute]
    n 1: an artificial or inferior substitute or imitation

Moby Thesaurus II by Grady Ward, 1.0:

141 Moby Thesaurus words for "ersatz":
   affected, agent, alike, alternate, alternative, analogy, aped,
   apocryphal, artificial, assumed, backup, bastard, bogus, brummagem,
   change, changeling, colorable, colored, comparison, consimilar,
   copied, copy, counterfeit, counterfeited, deputy, distorted,
   double, dressed up, dummy, embellished, embroidered, equal,
   equivalent, exchange, factitious, fake, faked, false, falsified,
   favoring, feigned, fictitious, fictive, fill-in, following, forged,
   garbled, ghost, ghostwriter, hokey, homogeneous, identical,
   illegitimate, imitated, imitation, junky, like, locum tenens,
   make-believe, makeshift, man-made, metaphor, metonymy, mimicked,
   mock, nearly reproduced, next best thing, not unlike, personnel,
   perverted, phony, pinch, pinch hitter, pinchbeck, plagiarized,
   pretended, provisional, proxy, pseudo, put-on, quasi, queer,
   relief, replacement, representative, resembling, reserve, reserves,
   ringer, second string, secondary, self-styled, sham, shoddy, sign,
   similar, simulacrum, simulated, smacking of, so-called, soi-disant,
   something like, spare, spares, spurious, stand-in, stopgap, sub,
   substituent, substitute, substitution, succedaneum, suggestive of,
   superseder, supplanter, supposititious, surrogate, symbol,
   synecdoche, synthetic, temporary, tentative, third string, tin,
   tinsel, titivated, token, twisted, unauthentic, understudy,
   ungenuine, uniform with, unnatural, unreal, utility,
   utility player, vicar, vicarious, vice-president, vice-regent,
   warped