e.g. The unwashed pot was still sitting on the stove the next day.
(adjective)
common or ignorant, somewhat coarse or crude in manner or style;
e.g. He didn't want to travel among the unwashed masses by taking public transportation.
(noun)
(usually derogatory) the lowest class of people in a society, those who are underprivileged and often common or ignorant (usually used as "great unwashed")
e.g. Many of the great unwashed never see these regions of country.