Korean is a dynamic language which exhibits the development of a variety of lexical nouns into grammatical markers. Among the many examples in the Korean language, cikyeng ‘boundary’ shows intriguing functional-semantic extension patterns. In other words, the item originally used as a free morpheme, functioning a main component in sentences and encoding a physical space or situation, became a stance marker - a negative function in present-day Korean. In this respect, this paper attempts to investigate the historical evolution of the lexical noun cikyeng from a grammaticalization perspective. As a full-fledged noun, the item shows diverse semantic and functional characteristics in present-day Korean as a lexical noun, a defective noun, and a nominalizer in reference to a negative marker. Considering the diversity of this single form as a result of the historical pragmatics and cognitive activities, this paper focuses on the analysis of the semantic-functional change that cikyeng underwent over time and the semantic extension patterns triggered by cognitive mechanisms. To examine the diverse paths and semantic development shown in the item, this paper suggests grammaticalization process that is largely enabled by the conceptual mechanisms along the image schema, and presents an explication of how the negative marking function emerges from a spatial and situational concept based on the cognitive forces that operate in language use. (Sahmyook University)