1. "Caveat." And this is especially problematic in my profession. We will be in a meeting. Someone says something. Someone else says, "I want to caveat off of that," before proceeding to either agree with or add something to what the previous person said.

ca·ve·at

noun

a warning or proviso of specific stipulations, conditions, or limitations.

There is nothing in that definition that suggests, or really leaves any room to interpret, that "caveat" is the same as "addendum."

2. "Irregardless." I won't post a definition here. This is just adding a syllable to an already existing word while saying exactly the same thing. Amazing how laziness involves more effort in this case.