Multidomain　dynamic　manipulations　for　terahertz　(THz)　absorbers　usually　necessitate　the　orchestrated　actions　of　several　active　elements,　inevitably　complicating　the　structural　design　and　elongating　the　modulation　time.　Herein,　we　utilize　the　coupling　between　the　total　reflection　prism　and　electrically-driven　MoS2　to　activate　a　tight　field　confinement　in　a　deep-subwavelength　interlayer,　ultimately　achieving　frequency-agile　absorption　adjustments　only　with　a　gate　voltage.　Theoretical　and　simulation　analysis　results　indicate　that　the　redistributed　electric　field　and　susceptible　dielectric　response　are　attributed　to　the　limited　spatial　near-field　perturbation　of　surface　plasmon　resonances.　We　also　demonstrate　that　perturbed　MoS2　plasmon　modes　promote　the　formation　of　dual-phase　singularities,　significantly　suppressing　the　attenuation　of　the　absorption　amplitude　as　large-scale　frequency　shifts,　thereby　extending　the　relative　tuning　range　(WRTR)　to　175.4%.　These　findings　offer　an　efficient　approach　for　expanding　the　horizon　of　THz　absorption　applications　that　require　ultra-broadband　and　swift-response　capabilities.　©　2023　The　Royal　Society　of　Chemistry.