| 1 | English | inauthentic | Not authentic or genuine; spurious |
| 2 | English | authentic | Of the same origin as claimed; genuine;... |
| 3 | Middle English | authentik | — |
| 4 | Old French | autentique | — |
| 5 | Latin | authenticus | original, genuine, authentic |
| 6 | Ancient Greek | αὐθεντικός | warranted, authentic, authoritative |
| 7 | Ancient Greek | αὐθέντης | a perpetrator of any act, especially that he... |
| 8 | Ancient Greek | αὐτο- | self- |
| 9 | Ancient Greek | αὐτός | αὐτή f, αὐτό n; "first/second declension";... |
| 10 | Proto-Indo-European | h₂ew | away from, off; again |
| 11 | Proto-Indo-European | ǵʰe | — |