What is a Noun Clause?
A noun clause has to do with the Beta Clause, which we also call a dependent or subordinate clause which performs the function of a noun in a sentence or functions like the nominal group. A noun serves as the subject of the verb in a sentence or it serves as the complement of the verb in a sentence; so does a noun clause and even a nominal or noun phrase.

For grammatical classifications that use ‘object’ instead of ‘complement’, noun clauses can equally stand as indirect or direct objects, nominatives (a grammatical form case of nouns and pronouns that identifies the subject of a sentence or clause), objects of a preposition. The following words can introduce a noun clause: what, that, where, why, when, which, whoever, whomever, and other such words. Let us illustrate what we have explained consider some examples:

Examples of Noun Clauses
What the man said is not clear (‘What the man said’ serves as the subject of the verb ‘is not’)
Where he went remains unknown.
Why he came here is not clear.
Which way to turn is a bit confusing.
Whoever wins the race goes home with fantastic prizes.
When he left the house was not recorded.
We will accept whomsoever she brings home
The noun/nominal clause usually answers the question ‘who’ or ‘what’. For instance:

We have been told that the examination starts this week. (We have been told what)
Who wins the tournament remains unknown. (What remains unknown?)
Leaving the school without permission could earn a student suspension. (What could earn a student suspension?)
Whoever arrives first is the winner. (Who is the winner?)
Whomsoever we vote for becomes our governor. (Who is our governor?)
As mentioned earlier, noun clause performs the same functions as a noun in different ways. Let us examine the broad functions of noun clauses…

See more: https://akademia.com.ng/what-is-a-noun-clause-types-functions-and-examples/