The contrastive approach in language teaching has renewed didactic relevance in modern classrooms where learners continuously shuttle between the native language (L1) and a foreign language (L2) through translation, digital media, bilingual schooling, and multilingual communication. While the strong “contrastive analysis hypothesis” has been criticized as a universal predictor of errors, research in second language acquisition and cross-linguistic influence confirms that semantic divergence between languages remains a major source of misunderstanding, negative transfer, and non-native-like lexical choice. This article examines the didactic value of contrastive instruction specifically for semantic differences, arguing that systematic comparison can function as a pedagogical tool for noticing, conceptual re-structuring, and prevention of interference in vocabulary and phraseology. Using an integrative analytical method, the study synthesizes insights from contrastive linguistics, lexical semantics, cognitive approaches to meaning, and classroom-based research on form–meaning mapping. The results propose a coherent set of teaching strategies that convert contrastive findings into learner-friendly semantic “decision procedures,” with emphasis on polysemy alignment, conceptual boundaries, pragmatic frames, and collocational norms. The paper concludes that the contrastive approach is most effective when it is selective, data-informed, and embedded in communicative practice, enabling learners to understand not only “what a word means,” but also “when and how it is used” in the target language.