Synonyms of the word

unauthentic

• adj. Not authentic.

counterfeit

• adj. False, especially of money; intended to deceive or carry appearance of being genuine.
• adj. Inauthentic.
• adj. Assuming the appearance of something; deceitful; hypocritical.
• n. A non-genuine article; a fake.
• n. One who counterfeits; a counterfeiter.
• n. (obsolete) That which resembles another thing; a likeness; a portrait; a counterpart.
• n. (obsolete) An impostor; a cheat.
• v. (transitive) To falsely produce what appears to be official or valid; to produce a forged copy of.
• v. (transitive, obsolete) To produce a faithful copy of.
• v. (transitive, obsolete) To feign; to mimic.
• v. (transitive, poker, usually "be counterfeited") Of a turn or river card, to invalidate a player's hand…

imitative

• adj. Imitating; copying; not original.
• adj. Modelled after another thing.

inauthentic

• adj. Not authentic or genuine; spurious.

spurious

• adj. false, not authentic, not genuine.
• adj. (archaic) bastardly, illegitimate.