This study examined the semantic distinctions among the synonymous Korean adverbs gojak (‘고작'), gikkeot (‘기껏'), gyewu (‘겨우'), bulgwa (‘불과'), and gikkeot-haeya (‘기껏해야') through a quantitative analysis based on co-occurrence data from the Sejong Corpus. Using hierarchical clustering and correspondence analysis, the study visualized the degree of semantic proximity among these adverbs.The hierarchical clustering results show that gikkeot and gikkeot-haeya form the closest semantic cluster, followed by gojak and bulgwa. In contrast, gyewu emerged as a semantically independent adverb, forming a distinct cluster. Correspondence analysis further confirmed these patterns by illustrating that gojak, gikkeot, and gikkeot-haeya are located near the origin and share similar directional vectors, indicating overlapping co-occurrence profiles. Meanwhile, bulgwa and gyewu are clearly separated in different quadrants of the plot, reflecting their distinct semantic and syntactic properties.By integrating co-occurrence patterns with statistical analysis, this study supplements intuition-based and dictionary-driven synonym classifications. The findings affirm that a corpus-based approach is effective in distinguishing subtle semantic differences among synonymous adverbs. Further research is needed to expand this analysis to a wider range of adverbs and to incorporate pragmatic and discourse-level factors into the investigation..