"The tall boy is a reporter."

Translation: A magas fiú riporter.

[artemiscrescent]

I wrote "A magas fiú riporter van." did I get incorrect because the van is automatically superfluous in this case?

[Shamarth]

Yes. You have to omit "van" (in third person singular and plural), when:

stating what something is using an adjective or a noun. (hungarianreference.com)

[deactivated user]

Why is "A fiú magas riporter" wrong?

[Ro_el_Conde]

Cause it means "The boy is a tall reporter". The adjective takes precedence in an attributive sentence, therefore before it is inferred the verb to be. :B