What are the two words that green would like us to refrain from using in the study of history?

In Crash Course History, John Green, an author, and educator explained that there are two words to refrain using in history. He identified it as the word "primitive" because it's not the right word to explain the condition of America when it was colonized, differences from the acquired technology or resources and attach it to being primitive is not a measurement. He explains that there is a linear development that should be considered where the primitive word does not fit. Another is "decimation", in history they use it to explain the decrease in population that caused by some event, however, decimation to some means a reduction of ten percent.