expression, noun
townspeople; ordinary citizens; the common people
A somewhat literary or formal expression referring to ordinary people living in a town or city, as opposed to those in power or of high status.
市井の人の声を政治に反映させるべきだ。
The voices of ordinary citizens should be reflected in politics.
一般人 is a very common word for 'ordinary person' or 'the general public', used in everyday contexts, whereas 市井の人 is more formal and less frequent.
市井 (しせい) originally referred to a town well or marketplace, a gathering place for common people, and by extension came to mean 'town' or 'the street'. Combined with 人 (ひと), the phrase literally means 'people of the town', i.e., ordinary townsfolk.