This study aims to trace the aspects of using verbs, ‘not-’ and ‘du-’, in history through corpus analysis in each period from the 15th to 20th century and figure out how the use of the words in synonymy has changed. With regard to the aspects of their semantic use in history, the two verbs went through polysemic division in their own area; however, in the process of polysemization, it has been found that their synonymic meaning did influence each other’s polysemy, too. While ‘not-’ was mainly used in the concrete area in the past, ‘du-’ was more often used in the area that was more abstract. Later, as ‘not-’ was being differentiated into a more abstract and diverse semantic area, it was grammaticalized into the area of an auxiliary verb or functional verb. And as the border between its previous meanings became clearer, more of the cases got fixed as a particular register. Unlike this, ‘du-’ maintained its lexical use in the abstract area; however, as the area of its use was relatively more flexible than that of ‘not-’, many of the cases could not establish any clear border of meaning. The changes in the meaning of ‘not-’ and ‘duda’ show dynamic aspects as associated with individual semantic difference and the changes of use in history. It is expected that in the future, this kind of research will concretely as well as practically verify that language changes dynamically within the dynamic structure of organically correlated various components.