This article is concerned with studying the influence of conservatism on the modern Arabic lexicography, namely the structure of its dictionary entries and interpretation methods. "The Large Arabic Dictionary" of the Academy of the Arabic Language in Cairo has been chosen as the object of research since lexicographers regard it as the newest stage in the centuries-long evolution of the Arabic lexicography. Based on "The Large Arabic Dictionary", the comparative analysis touches upon the peculiarities of a modern general purpose dictionary of the Arabic language, definitions, methods of recording primary and derived verbs, and types of supporting data. The consistency between modern dictionaries of the Arabic language and their classical, medieval counterparts is analysed with regard to methods of organisation and interpretation. Omissions made by medieval lexicographers due to complex definitions and unsystematised dictionary entries are critically examined.