The paper highlights the notion of deontic meaning, understood as a component of the descriptive meaning of a word or a phrase, expressing both an assessment and a volitive modality indicating how a word ought to be used in a certain context to denote a certain content. The analysis is in line with the concept of cultural keywords that at certain periods of time stand out in public discourse and begin to be put forward to express socially significant meanings. The adopted notion of a key word is in favour of conceptualising salient lexics in discourse, the analysis argues that key words are associated with social actors, political parties, tied to the essential characteristics of their political agenda, can be used to express alternative values and competing concepts. The deontic meaning of the linguistic item westliche Werte (western values) in German public discourse is revealed. The analysis is carried out as a corpus-guided noncritical discourse analysis. The selection of contexts was carried out on the Digital Dictionary of Contemporary German. A corpus of political speeches and the newspaper corpus “Frankfurter Allgemeine Zeitung” were used. The search period is 2014–2023. It was found that in German public discourse westliche Werte acts as a flag word with a positive deontics when referring concepts that shape the self-understanding and self-representation of German society and its collective “us”-identity. In connection with alternative ideologies, political views, this key word acquires the characteristics of a stigma keyword with pejorative semantics of rejection. The article advocates the suitability of the deontic meaning as a tool in the study of semantic and axiological polysemy due to the ideological polarization of social actors standing behind the expressed concept.