This study aims to research the modification of ‘먹다’ and ‘다’ in the modern language, and proceeds identify their synonymy through their syntactic-semantic relationship and translation of Sino-Korean words. For the syntactic-semantic relationship, the ‘NP1-이 NP2-를 먹다/ 다.’ sentences was the main focus of attention. The first, sentence addresses the basic meaning of the two words, and the second, the semantic extensions that function as polysemous expressions. Identification of the synonymic-relationship between the two words in the modern language was possible by first, by comparing and contrasting the Sino-Korean word and the native Korean word through translation, second by comparing the objects (target roles of NP2) in the predicates of ‘NP1-이 NP2-를 먹다/다’ sentences, finally through the certification of the opposite meaning. (Kansai Univ.)