It has long been argued that linguistic synesthesia has a universal linear-hierarchical directionality tendency, which is mostly grounded in Indo-European language data. This study explores linguistic synesthesia in Korean to verify the cross-linguistic generalizability of the universality hypothesis of linguistic synesthesia. Based on synesthetic data from the Sejong Corpus and gustatory adjectives, this study found that Korean synesthesia shows language-bound variations with three different types of mappings (i.e., unidirectional, reciprocal, and biased), which are frequency- and rule-based. This finding challenges the cross-linguistic universality of the mapping directionality of linguistic synesthesia. As for the mapping mechanism of linguistic synesthesia, this study supports the embodiment theory in terms of language-specific variation. Additionally, it has been proposed that linguistic synesthesia is a special type of metaphor based on both rules and frequency. Finally, this study suggests that linguistic synesthesia displays universal directionality at a general level and language-bound variation at a specific level.