silence is golden
A proverb meaning that speaking too much can bring trouble, so it is better to remain silent. The imagery is of autumn wind making one's lips feel cold after speaking.
As the saying goes, 'Silence is golden,' so it's better not to say unnecessary things.
A more direct translation of 'silence is golden,' often used in modern contexts, while 物言えば唇寒し秋の風 is a traditional Japanese proverb with a seasonal image.
A verse by 松尾芭蕉, recorded as a personal maxim: 物いへば唇寒し秋の風. It subsequently became proverbial as a warning about the consequences of speaking.