There is no meaning inwhat you are saying.Here the underlined part is a/an -

• There is no meaning in what you are saying. here the underlined part is a - Noun clause.
- A noun clause is a group of words that band together and act like a noun. Nouns clauses are used when a single word isn't enough. They're always dependent clauses.

একটি বাক্যের চারটি স্থানে Noun clause  বসতে পারে -
1. subject হিসাবে 
2. transitive verb এর object হিসেবে
3. Linking verb এরপরে complement হিসাবে 
4. Preposition এরপরে

প্রদত্ত বাক্যে "what you are saying" clause টি Preposition এরপরে object হিসাবে বসেছে, তাই এটি Noun clause.