authentic

authentic is an Adverb

Definition:

[1] Having a genuine original or authority, in opposition to that which is false, fictitious, counterfeit, or apocryphal; being what it purports to be; genuine; not of doubtful origin; real; as, an authentic paper or register. To be avenged On him who had stole Jove`s authentic fire. Milton.

[2] Authoritative. [Obs.] Milton.

[3] Of approved authority; true; trustworthy; credible; as, an authentic writer; an authentic portrait; authentic information.

[4] Vested with all due formalities, and legally attested.

[5] Having as immediate relation to the tonic, in distinction from plagal, which has a correspondent relation to the dominant in the octave below the tonic.