Here’s the sort of spooky thing. It’s not just that there are multiple generations who’ve never known a “jerk” was once a simpleton or sap. It’s that some of the folks who used to use it that way don’t remember that they did. When I asked my mom to define the word this week, she used the modern meaning, with no apparent recollection of her former firm conviction that a jerk was a dope, dodo, or dimwit.

I am gen-X and I have no recollection of that former meaning at all. I was 10 or 11 years old when the movie The Jerk came out, and I recall being mildly confused about the fact that he didn't really seem like a jerk, and sort of thinking that he must be acting that way on purpose.

I'm around that age and still have "some poor jerk" in my vocabulary. Any other use than that specific one still has the modern meaning for me.

I was an adult in my twenties when that movie came out and thought the title was odd as it didn’t seem to fit him. Maybe I had already transitioned from idiot to mild asshole.

I have the same memory but no idea if that is a real memory or a false one. Being Gen X, most of my meaning for the word jerk came from Devo and the Circle Jerks.