I think you're very close to being right...

But I think "Fuck you money" implies, "I honestly don't have to worry about money, ever again."

Now, we all have different definitions for that, but the kind of thing I was talking about is definitely not "Fuck you money," to me.

I think if I had "Fuck you money," my best friends and close family would all have their medical debts paid off. I think my parents and in-laws would have their mortgages paid off.

It’s more than just money, it’s how you set up your life to be resilient to contingencies. For example finding a compatible life partner. For example finding happiness without lifestyle inflation and breaking free from the hedonic treadmill. Or perhaps having a good lifestyle business for some people. Or having extended family support nearby. I call these things unfuckwithability. Money is a big part of it, but may not be the biggest missing piece for many people.