A rational argument is an argument that follows some sort of logical thought process, it has nothing to do with whether the conclusion is correct or not.

This is a rational argument:

• Premise 1: The Earth is a planet.
• Premise 2: The Earth is flat.
• Premise 3: All flat planets have edges.
• Conclusion: The Earth has edges.

Premise 2 is false, and premise 3 is unknown, so the conclusion is false, but it follows a logical thought process and isn't nonsense.

This is nonsense and irrational:

• Premise 1: Apples are round.
• Premise 2: Pyramids exist.
• Premise 3: Unicorns have horns.
• Conclusion: Aliens!

There is no discernible logic or rational thought process. It is just apparently random statements with no connection.

• https://www.merriam-webster.com/dictionary/reason
• https://www.merriam-webster.com/dictionary/nonsense
• https://simple.wikipedia.org/wiki/Argument_from_false_premises
• https://thelogicofscience.com/2017/03/27/the-fallacy-fallacy-reject-the-argument-not-the-conclusion/

Again, since we can't even agree on commonly accepted definitions for basic concepts, we just aren't going to be able to have any kind of productive conversation.

Good day.