Slang lagged
When someone's slang is 5 years behind and if they encounter modern slang they will proceed to misuse it and as often as possible. Usually found in sheltered/homeschooled kids, but not always.
Person 1: "Hey did you see Kevin? He was flossing and get this, he thought he was being cool!"
Person 2: "Rip bozo so slang lagged"
Person 2: "Rip bozo so slang lagged"