What's the difference between orotund and orotundity?

Orotund

Definition:

• (a.) Characterized by fullness, clearness, strength, and smoothness; ringing and musical; -- said of the voice or manner of utterance.
• (n.) The orotund voice or utterance

Example Sentences:

• (1) who and whom When Groucho Marx was once asked a long and orotund question, he replied, "Whom knows?"

Orotundity

Definition:

• (n.) The orotund mode of intonation.

Example Sentences:

• (1) who and whom When Groucho Marx was once asked a long and orotund question, he replied, "Whom knows?"