My grandmother (born around the time Ireland gained independence from the UK) used "Irish" to mean "stupid" shortly before her Alzheimer's diagnosis.

When my mother (born during WW2) also got an Alzheimer's diagnosis, she started using "glory hole" to refer to the kitchen cupboard. (I had to look it up, but it's apparently a legit though obsolete meaning).

"Democratise" is my personal bugbear. Doesn't have anything to do with voting or dispute resolution.

My dad had a problem with the words "millennium" not being used for the period starting Jan 1, 2001, and the word "gay" switching from the mid-20th-century meaning to the late-20th-century meaning.

...

/s