Words and phrases that didn't exist yet. Like: "bleed out" used by ordinary people in the 1970s or even before. I don't know how long normies have used the term but my wild guess is the 1990s maybe.

Ninja edit. Stranger Things had stuff like: "trust issues", "stay frosty", "I think I just threw up in my mouth." etc. I stopped making a list because I tried to ignore all of them.