What part of speech is master in the sentence. Advertisements promised instruction from a teacher?

Let's break down the sentence to figure out the part of speech of "master":

* Advertisements promised instruction from a teacher.

The sentence is a complete thought and has a subject (advertisements) and a verb (promised). The word "master" is not present in this sentence.

Therefore, we cannot determine the part of speech of "master" in this sentence because it does not appear in the sentence.