The difference between Authentic and Ungenuine

When used as adjectives, authentic means of the same origin as claimed, whereas ungenuine means false, not genuine or authentic.

check bellow for the other definitions of Authentic and Ungenuine

Authentic as an adjective:

Of the same origin as claimed; genuine.

Examples:

"The experts confirmed it was an authentic signature."
Authentic as an adjective:

Conforming to reality and therefore worthy of trust, reliance, or belief.

Examples:

"The report was completely authentic."

"an authentic writer; an authentic portrait; authentic information"
Authentic as an adjective (music, of a [[Gregorian mode]]):

Having the final as the lowest note of the mode.
Authentic as an adjective (obsolete):

authoritative