This linguistic study delves into the intricate world of Assamese lexical word categories by focusing on derivational morphology. Assamese, a language rich in cultural heritage, exhibits a complex system of word formation, with derivational processes playing a crucial role in the expansion and diversification of its lexicon. Through a meticulous analysis of derivational affixes, processes, and their semantic contributions, this research aims to decode the structure and evolution of word categories in Assamese. By shedding light on the ways in which derivational morphology shapes lexical word categories, this study contributes to a deeper understanding of the language's unique linguistic features.