The difference between Authentic and Fake

When used as adjectives, authentic means of the same origin as claimed, whereas fake means not real.

Fake is also noun with the meaning: something which is not genuine, or is presented fraudulently.

Fake is also verb with the meaning: to cheat.

check bellow for the other definitions of Authentic and Fake

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

Fake as an adjective:

Not real; false, fraudulent.

Examples:

"Which fur coat looks fake?"
Fake as an adjective (of people):

Insincere.

Fake as a noun:

Something which is not genuine, or is presented fraudulently.
Fake as a noun:

A trick; a swindle.
Fake as a noun (sports):

A move meant to deceive an opposing player, used for gaining advantage for example when dribbling an opponent.

Fake as a verb:

To cheat; to swindle; to steal; to rob.
Fake as a verb (archaic):

To modify fraudulently, so as to make an object appear better or other than it really is
Fake as a verb:

To make a counterfeit, to counterfeit, to forge, to falsify.
Fake as a verb:

To make a false display of, to affect, to feign, to simulate.

Examples:

"to fake a marriage"

"to fake happiness"

"to fake a smile"

Fake as a noun (nautical):

One of the circles or windings of a cable or hawser, as it lies in a coil; a single turn or coil.

Fake as a verb (nautical):

To coil (a rope, line, or hawser), by winding alternately in opposite directions, in layers usually of zigzag or figure of eight form, to prevent twisting when running out.