He talks a lot without saying anything of substance, just like an empty vessel.
Он много говорит, не говоря ничего по существу, как пустой сосуд.
Definitionen
An 'empty vessel' is a metaphorical phrase used to describe a person who talks a lot but lacks knowledge, substance, or wisdom. It originates from the proverb 'Empty vessels make the most noise,' implying that those with little to offer often make the most fuss or draw the most attention.
