Empty vessels make the most sound. とはどういう意味ですか?

質問を翻訳

A vessel is a container.
An empty container makes a loud, hollow sound when tapped. Think about an empty jar and a filled jar. The full jar makes only a dull sound, not very loud; the empty jar rings loud and clear, like a bell.

The idiom “Empty vessels make the most sound” means that people who talk a lot, always wanting to give you their opinions, usually are not very intelligent. Intelligent people are quiet people, by comparison.