Originalism is sort of subspecies of textualism. Textualism means you are governed by the text. That's the only thing that is relevant to your decision, not whether the outcome is desirable, not whether legislative history says this or that. But the text of the statute.

Power tends to corrupt. But the power in Washington resides in Congress, if it wants to use it. It can do anything - it can stop the Vietnam War, it can make its will felt, if it can ever get its act together to do anything.

Originalism says that when you consult the text, you give it the meaning it had when it was adopted, not some later modern meaning.

Antonin Scalia Quotes