This paper presents the central finite-dimensional Hinfin filter for nonlinear polynomial systems, that is suboptimal for a given threshold gamma with respect to a modified Bolza-Meyer quadratic criterion including the attenuation control term with the opposite sign. In contrast to the previously obtained results, the paper reduces the original Hinfin filtering problem to the corresponding optimal H2 filtering problem, using the technique proposed. The paper designs the central suboptimal Hinfin filter for the general case of nonlinear polynomial systems, based on the optimal H2 filter given. The central suboptimal Hinfin filter is also derived in a closed finite-dimensional form for third (and less) degree polynomial system states. Numerical simulations are conducted to verify performance of the designed central suboptimal filter for nonlinear polynomial systems against the central suboptimal Hinfin filter available for the corresponding linearized system.