A common example would be a famous story on Internet that spawned a meme where someone accidentally combined "Are you okay?" and "I'm fucking sorry" and ended up saying "Are you fucking sorry?"
A recent example was when someone I was discussing something with accidentally combined "handy" and "useful" and ended up saying that it was "handful". (If something is "a handful" then it's pretty problematic, not very useful.)
This kind of mixup when you two thoughts with the same meaning accidentally combine into something with the opposite meaning happens so often that there must be a word for it. I'm looking for that word.
Such a word would be used in a sentence like this:
Sorry, I just had an X.
X happens to me a lot, but when it does I usually catch it before I actually say it.
I'm thinking it could be something like "antonymic synonym compound", because it compounds two nearly synonymic thoughts into an antonymic sentence, but this really isn't my field at all so I'm just talking in my night cap. If there's a word for it then it's probably more psychology oriented rather than linguistics.
Should I maybe have asked this in the Psychology StackExchange instead?