The rapid expansion of social media platforms has fundamentally transformed patterns of communication, particularly among Generation Z (Gen Z), who constitute the most digitally immersed cohort in contemporary society. In Bangladesh, the increasing prevalence of obscene, vulgar, indecent, and offensive language on social media has emerged as a significant social, cultural, and psychological concern. This study investigates the patterns, motivations, and socio-psychological contexts of vulgar and indecent language use in digital communication among Bangladeshi Gen Z users. Employing a quantitative survey-based methodology complemented by contextual qualitative observations, the research examines how anonymity, algorithmic amplification, peer culture, emotional expression, and online disinhibition shape linguistic behaviour in social media environments. Drawing upon theoretical frameworks such as Online Disinhibition Theory, Media Ecology, and Sociolinguistic Norm Shift theory, the study reveals that vulgar language is not merely a linguistic deviation but a complex form of digital expression shaped by platform architecture, youth identity formation, and socio-political frustration. The findings highlight a growing normalization of offensive speech, a decline in linguistic civility, and the emergence of vulgarity as a symbolic tool for visibility, resistance, and emotional release. The study contributes to scholarly debates on digital incivility, youth culture, and media ethics in the Global South and offers policy-relevant insights for educators, platform regulators, and digital literacy initiatives in Bangladesh.