Explanation:

- Fake: Something that is not genuine or is meant to deceive; an imitation or a counterfeit.

- Option 1, Real: Means authentic or true; opposite of fake.

- Option 2, Genuine: Describes something that is truly what it is said to be; authentic and real.

- Option 3, False: Not true or correct; often used as a synonym for fake.

- Option 4, Factual: Based on or concerned with fact; opposite of fake.

The closest synonym to "fake" is false, as both imply something untrue or deceitful. The other options have meanings that are not synonymous with fake.

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