A mathematical decision-making model in Ill-defined dynamic situations focused on supporting the activities of the decision-maker in the processes of constructing and transforming the situation semiotic model is proposed. Support is based on the extraction and processing of information from the Internet that is relevant to the situation semiotic model. The semiotic model is based on the model of intelligence as a form of organization of a person’s mental experience, which is described using three models related by parameters: syntactic, semantic, and pragmatic. The decision support method is based on the support of the intellectual activity of the decision-maker in the interpretation of the decision class names formally obtained in the semiotic model. Methods for interpreting the decision class names based on extracting relevant information from the Internet are proposed. Using lexical-semantic templates in the text corpus of the subject area, generic dictionaries, and a context dictionary is defined. Based on the methods of distributive semantics (word2vec), a semantic calculator is built that allows you to determine the meaning of the names of solution classes. The effectiveness of this method is to reduce the routine analytical work of experts in the interpretation process of formal solutions in the subject area that it improves intellectual productivity. Experimental verification of the proposed model confirms its effectiveness.