Antonyms of adj authentic

2 senses of authentic

Sense 1
authentic, reliable -- (conforming to fact and therefore worthy of belief; "an authentic account by an eyewitness"; "reliable information")

INDIRECT (VIA trustworthy) -> untrustworthy, untrusty -- (not worthy of trust or belief; "an untrustworthy person")

Sense 2
authentic, bona fide, unquestionable, veritable -- (not counterfeit or copied; "an authentic signature"; "a bona fide manuscript"; "an unquestionable antique"; "photographs taken in a veritable bull ring")

INDIRECT (VIA genuine) -> counterfeit, imitative -- (not genuine; imitating something superior; "counterfeit emotion"; "counterfeit money"; "counterfeit works of art"; "a counterfeit prince")

Similarity of adj authentic

2 senses of authentic

Sense 1
authentic, reliable -- (conforming to fact and therefore worthy of belief; "an authentic account by an eyewitness"; "reliable information")
       => trustworthy (vs. untrustworthy), trusty -- (worthy of trust or belief; "a trustworthy report"; "an experienced and trustworthy traveling companion")

Sense 2
authentic, bona fide, unquestionable, veritable -- (not counterfeit or copied; "an authentic signature"; "a bona fide manuscript"; "an unquestionable antique"; "photographs taken in a veritable bull ring")
       => genuine (vs. counterfeit), echt -- (not fake or counterfeit; "a genuine Picasso"; "genuine leather")