Modern English is characterized by a desire to integrate various syntactic means. Syncretism is the main tool that helps neutralize asymmetric language relationships and the limited functional nature of the units. In the English language the growth of a large number of syncretic complex sentences is connected, first of all, with the desire of the speaker to convey complicated semantic meanings with the help of polyfunctional constructions where subordinate clauses function both as carriers of a single meaning and convey additional information. The development of an additional meaning occurs as a result of the semantic mobility of subordinate parts. That is, the intermediate character of the models indicates a high degree of complexity of the semantic structure and a considerable potential of semantic meaning. The purpose of the work is to investigate the internal organization of English complex sentences taking into account their structural and semantic features; to analyze the role of the influence of relevant words and connecting elements at the sentence level in order to clarify the content and linguistic aspects of complex sentences. The reliability of the analysis results is ensured by the use of various research methods and techniques. The leading methods in the work are general scientific methods (the method of observation, the method of analysis and synthesis), special methods (the comparative method, the method of component analysis, the descriptive method, the method of component and oppositional analyzes with the techniques of grouping complex sentences, the comparative method, the modeling method, functional-semantic analysis) The scientific novelty of the research lies in the fact that the paper attempts to analyze syncretic English complex sentences based on the semantic field and to describe the semantic potential of complex constructions taking into account the functional-semantic field in the English language. Conclusions. When analyzing and studying complex sentences in view of the influence of functional -semantic field and syncretism, the fact is established that the functionalsemantic fields are interconnected and realize their most significant shades of meaning precisely in the peripheral zones that testifies to the flexibility of the hypotaxis system and its dynamic nature.