Where does “authentic” come from?

Authentic comes from Middle English authentik, from Old French autentique, from Latin authenticus, from Ancient Greek αὐθεντικός, derived from αὐτός meaning self.

authentic (English): Of the same origin as claimed; genuine;...

Definitions

Of the same origin as claimed; genuine;...

Ancestry of “authentic”, step by step

Step	Language	Word	Meaning
1	Middle English	authentik	—
2	Old French	autentique	—
3	Latin	authenticus	original, genuine, authentic
4	Ancient Greek	αὐθεντικός	warranted, authentic, authoritative
5	Ancient Greek	αὐθέντης	a perpetrator of any act, especially that he...
6	Ancient Greek	αὐτο-	self-
7	Ancient Greek	αὐτός	αὐτή f, αὐτό n; "first/second declension";...
8	Proto-Indo-European	h₂ew	away from, off; again
9	Proto-Indo-European	ǵʰe	Postpositional intensifying particle: indeed, at any rate, in fact

Words derived from “authentic”

Every word from Proto-Indo-European ǵʰe →Every word from Proto-Indo-European h₂ew →Every word from Ancient Greek αὐτός →