I don’t know if there’s a word for this behavior, but it’s a staple of Marxist debate. They jump back and forth from the common definition of words to the technical or “jargon” definition. You caught a perfect example: “centrally planned” is a very specific idea in economics, but it is also a phrase made up of common words, and a bad actor (as all leftist debaters are) can use this fact to twist definitions and “win” arguments.