There's inflation (to get bigger) and conflation (to bring together). You may have heard people say something like "she's muddying the waters," evoking the idea of someone stirring up the dirt so you can't tell where the water begins and the dirt ends. Or two rivers coming together like the mighty Rio Solimoes (the Amazon) and the Rio Negro.
In arguments, conflation is used when you try to point out to your opponent (or audience) that the thinker is taking one thing and confusing it or muddling it up with another. An example might be something like:
Hitler was a terrible person. He was really immoral.
Hitler believed that the world was round.
The world can't be round, because Hitler was immoral.
Oops, you're conflating Hitler's moral character (or lack thereof), with a statement of truth or falsehood; whether the world is flat or not. We're conflating two separate logical concepts. The world either is, or is not flat, independent of Hitler's moral …