AFAICT the "not true scotsman" is motte-and-bailey applied to the definition of a word - the fallacy isn't the original definition of the word "scotsman", the f

AFAICT the "not true scotsman" is motte-and-bailey applied to the definition of a word - the fallacy isn't the original definition of the word "scotsman", the fallacy is re-defining the word to mean something different and more defensible when you're challenged, and then to redefine it back to the original definition later, to re-include all the insufficiently-burly scots.