1. (n.) 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.

2. (n.) Authoritative.

3. (n.) of approved authority; true; trustworthy; credible.

4. (n.) Vested with all due formalities, and legally attested.

5. (n.) 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.

6. (n.) An original (book or document).

Christian aboveboard absolute accepted accurate actual adducible admissible approved attestative attestive authoritative avant-garde based on bona fide candid canonical card-carrying cathedral certain circumstantial cognizable conclusive conventional convincing correct creative credible cumulative customary damning de facto decisive dependable determinative dinkum documentary documented evangelical evidential evidentiary ex cathedra ex parte eye-witness factual fair and square faithful final firm firsthand following the letter for real founded on foursquare fresh genuine good good-faith grounded on hearsay historical honest honest-to-God imaginative implicit inartificial incontrovertible indicative indisputable indubitable irrefutable irresistible knowable lawful legitimate lifelike literal magisterial material natural naturalistic new novel nuncupative of the faith official on the level on the square on the up-and-up open open and aboveboard original orthodox orthodoxical overwhelming positive presumptive probative proper pukka pure questionless real realistic received recognizable reliable revolutionary right rightful scriptural significant simon-pure simple sincere single-hearted solid sound square square-dealing square-shooting standard sterling straight straight-shooting substantial suggestive sure sure-enough symptomatic telling textual traditional traditionalistic TRUE true to life true to nature true to reality true-blue trustworthy trusty unadulterated unaffected unalloyed unassumed unassuming uncolored unconcocted uncopied uncounterfeited undeniable underived undisguised undisguising undisputed undistorted undoubted unexaggerated unfabricated unfanciful unfeigned unfeigning unfictitious unflattering unimagined unimitated uninvented unique unpretended unpretending unqualified unquestionable unromantic unsimulated unspecious unsynthetic unvarnished up-and-up valid verbal verbatim veridical verisimilar veritable very weighty word-for-word