When Donald Trump learns new information that most people have known for a long time, and then he explains it to us in the way that it was just explained to him as if he's teaching us something that we didn't already know. Often preceded by the phrase "many people don't know..."
Donald Trump was Trumpsplaining when he said, "Many people don't know that Abraham Lincoln was a Republican."
When Donald Trump says what he really feels. His supporters see it could be a damning statement then twist the story explain what he meant to say even though it isn't.
"Why wouldn't Trump denounce white supremacy during the first 2020 presidential debate?"
"Trump has always denounced white supremacy, he didn't need to. When he said stand back and stand by, he meant to let them by."
"You don't have to Trumpsplain to me why you support a racist."
A door wall is a sliding-glass door or patio door. The term is yet another example of banal Michigan vernacular, where in the residents latch on to company names, trademark names, marketing terms and product names from local companies. The terms become embedded in the local vocabulary and eventually become accepted as actual valid words and phrases. In this case the term comes from Wallside Windows in Taylor, MI (a large window manufacturer), where 'door wall' is their created word for sliding-glass door.
"Bob! John's gonna bring over them doorwalls from Wallsides on Tuesdee afternoon 'round two-thirty. Get 'er done!"