Authenticity (noun)

1. The quality of being genuine, real, or of having been produced in accordance with traditional or original methods.
2. The quality of being true, accurate, or sincere.
3. The quality of being in accordance with an original or a claimed authority or origin.

Origin:

From the french word 'authenticité' meaning genuineness, and derived from the latin word 'authenticus' meaning original, genuine, or authoritative.

Examples:

1. The authenticity of the painting was confirmed by the experts.
2. The authenticity of the ancient ruins was verified through carbon dating.
3. Her performance was praised for its authenticity and emotional intensity.
4. The authenticity of the document was challenged in court.
5. The authenticity of the claim is still under investigation.