One of my favorite funny lines from 'Back To the Future' 1985 is when Michael J Fox's character says to Doc 'heavy' and Doc says, "There's that word again, heavy. Why does everything weigh so much in the future?". He doesn't realize he's not talking about physical weight, he's talking about stress and 'heaviness' on the mind from complex decisions. The term 'heavy' was probably coined in the 60s or 70s but IDK could've existed before then.