Yinzer is a 20th-century term playing on the Pittsburgh, Pennsylvania second-person plural vernacular "yinz." The word is used among peoples who identify themselves with the city of Pittsburgh and its traditions.
"Yinzer" (or "Yunzer") was historically used to identify the typical blue-collar people from the Pittsburgh region who often spoke with a heavy Pittsburghese accent. The term stems from the word yinz (or yunz), a second-person plural pronoun, brought to the area by early Scots-Irish immigrants. Over time, yinzer has been used by many Pittsburgh residents to self-identify, even if they didn't speak with a thick accent.
The concept and use of the word gained popularity in the 21st century as the area's population loss slowed, and the city became a hub for revitalization. As the city gained note as a desirable place to live, more outsiders have moved or returned to the Pittsburgh metropolitan area. The term has taken on a slight pejorative connotation to identify someone who, for better or worse, is either a lifelong Pittsburgher, or who commits an act that could be identified as something a less "sophisticated", stereotypical Pittsburgher might do.