This article discusses the design of a new type of dictionaries, the Active Learner’s Construction-Combinatory Thesaurus (ALCCT) intended for adult learners of the second (foreign) language. The ALCCT is an ideographic dictionary where phrases, understood as instantiations of constructions, are arranged in accordance with the cognitive ontology of a particular conceptual thematic field. As such, the ALCCT is a project compatible with cognitive lexicography, a contemporary branch of dictionary-making that adopts the findings of cognitive science, cognitive linguistics in particular. The article proposes a cognitive profile of the dictionary’s target user, and makes it a departure point in elaborating the principles of compiling the ALCCT. They are defined as the principles of data selection, arrangement, and application. Data selection regards their thematic and formal coherence, their authenticity, and their prominence, or frequency. Data arrangement implies their relational coherence, and their elaboration. Relational coherence is realized through the lexicographic code, or the dictionary’s overall design that develops at three hierarchical levels: those of macrostructure (a conceptual ontology of the theme), mediostructure (the key words evolving into phrasal sets), and microstructure (description of phrasal lemmas). Elaboration of the data is provided via the overarching structure mapped onto the three hierarchical structures of the lexicographic code, and concerned with etymological, cultural, grammatical, and phraseological (metaphorical) extensions. Data application reaches out to the communicative situations in which the ALCCT’s resources can be used.