Across many authoritarian and hybrid regimes, parliamentary chambers are characterised by conspicuous patterns of silence, limited questioning, ritualised affirmation, and restrained legislative engagement despite their formal mandate to deliberate and scrutinise executive power. This paper examines this paradox and challenges prevailing interpretations that treat parliamentary inactivity primarily as evidence of institutional weakness, democratic decline, or political apathy. Drawing on a qualitative, interpretive, and theory-building approach that synthesises parliamentary records, observational materials, and extant scholarship across selected authoritarian and hybrid contexts, the study identifies recurring behavioural patterns through which legislative inactivity acquires political significance. The analysis demonstrates that parliamentary silence and minimal engagement function as structured forms of political behaviour embedded within broader regimes of surveillance, patronage, institutional discipline, and symbolic power. Rather than representing the absence of politics, these observable patterns contribute to the reproduction of legislative order, the management of political risk, and the maintenance of regime stability. Building on these insights, the paper advances Performative Inactivity Theory (PIT) as a novel interpretive framework for explaining how patterned inactivity operates as a politically functional mode of legislative participation under conditions of authoritarian constraint. By shifting analytical attention from what legislators fail to do to what observable inactivity accomplishes within institutional settings, the paper offers a new behavioural perspective on authoritarian governance, legislative politics, and political sociology.