"Teacher, why is this word important?"
Translation:Opettaja, miksi tämä sana on tärkeä?
The subject is before the verb in a question that begins with an interrogative word, but that doesn't necessarily mean that the verb has to go all the way to the end of the sentence. As a subject predicative, "tärkeä" has to be placed after its copula, i.e. the linking verb that links it to the subject.