This article examines lexical and semantic deviations in the language use of Generation Z (Gen Z) in Nigeria, analysing how such deviations function as tools of creativity, identity, and communication in digital spaces. Despite extensive studies on Nigerian English, little attention has been given to the emerging, unconventional linguistic practices of Gen Z, particularly the role of digital technologies in driving their diffusion and the implications for intergenerational communication. The data collection process involved non-participant observation of online conversations, trending hashtags, memes, and other digital interactions. Slang terms and phrases were identified, recorded, and cross-checked with online slang dictionaries, blogs, and user-generated content to ensure reliability. Each lexical item was documented alongside its contextual usage, allowing for an accurate analysis of meaning in practice. This study systematically analyses twenty linguistic data drawn from Instagram, Facebook, and Twitter, focusing on their semantic shifts, lexical innovations, and syntactic deviations from Standard English. Anchored in William Labov’s variationist theory (1966), the study adopts a sociolinguistic qualitative design, using purposive sampling to select relevant data and employing qualitative content. Analysis to categorise deviations based on their type, standard meaning, and social meaning. Findings reveal that Gen Z’s linguistic practices are not anomalies but deliberate strategies that serve to index social belonging, redefine conventional meanings, and facilitate cultural expressions. The study concludes that language use by Gen Z reshapes the lexico-semantic norms of English, highlighting broader implications for intergenerational communication, linguistic evolution, and sociocultural identity.