Adjectives always describe nouns or pronouns, so adjective clauses are dependent clauses that describe nouns. Ex: Emily, whose name is on the board, talks too much during class. whose name is on the board describes the noun Emily. It is an adjective clause.
Adverbs describe other adverbs, verbs, or adjectives. Adverb clauses are dependent clauses that describe adverbs, verbs, or adjectives. Ex: The judge listened when the defendant pleaded his case. When the defendant pleaded his case describes the verb listened. It is an adverb clause.
Noun clauses DO NOT describe anything! They are dependent clauses that act as one big noun. Ex: Whatever you want is fine with me. Whatever you want is the noun clause. You could mentally replace it with a single-word noun if doing so helps you to better understand the material.
Whatever you want is fine with me. You could mentally replace this clause with one word, such as pizza. Pizza is fine with me. Therefore, we now easily see that whatever you want is a noun, and actually acts as the subject.
Noun clauses do not modify or describe anything, but they do act in several ways. Nouns can be: Subjects Direct objects Indirect objects Predicate nouns Objects of a preposition phrase
Whoever wants to go is welcome. Subject Lisa smashed whichever plate she could. direct object
Mary gave whomever would listen a piece of her mind. Indirect object The fence you are looking for is that one over there. Predicate noun We are praying for whichever outcome is best. Object of the PP