_{The article deals with military phraseology as a systemic linguistic phenomenon in the works of military theorists. The relevance of the research is conditioned by the necessity of complex analysis of professional phraseology in the conditions of international military cooperation development. In order to describe the specifics of phraseological units in military-scientific discourse, the objectives are to identify the repertoire and classify phraseological units according to structural and semantic features, to determine the functional specificity of different types of phraseological units, analyse the internal form as a key system-forming factor, investigate the main conceptual metaphors underlying military phraseology and their role in military discourse, identify and analyse the internal and external relations in the system of military phraseology. On the material of the works of outstanding theorists of military art (C. von Clausewitz, A.A. Svechin, M.N. Tukhachevsky, B.H. Liddell Hart, etc.) using the methods of corpus linguistics and cognitive analysis the types of military phraseologisms are identified and classified, their functional features are determined. The scientific novelty of the study lies in the integration of structural-semantic and cognitive approaches to the study of military phraseology. It is proved that the system-forming factor of military phraseology is the internal form, which is based on the metaphors of space, movement and organism. Internal and external systemic relations of military phraseological units are revealed, the phenomena of synonymy, antonymy and phraseological variation allow us to consider military phraseology as an integral system reflecting the specificity of conceptualisation of military reality.}