[en] The study of the magnetic excitations in Mn-rich alloys should be a good test of the multiband calculations of the spin dynamics of pure γ-Mn, which is a prototypical itinerantelectron antiferromagnet. In this paper we report the results of recent neutron inelastic scattering measurements performed on Mn₉₀Cu₁₀ at room temperature (T = 0.63 T_N) and up to 300 meV of energy transfer. These measurements were performed using the HET chopper-spectrometer at the ISIS spallation neutron source, Rutherford Appleton Laboratory, U.K. The results have been compared with calculations using a model scattering function convoluted with the full HET resolution function. In this model there is a steep linear spin-wave dispersion (D ∼ 250 meV-Angstrom) for wavevectors up to ∼ 1/2 of the Brillouin zone and a strong damping which is linear in the wavevector q. For larger wavevectors the spin-wave energies are constant at about 190 meV. These features are qualitatively similar to the predictions of Cade and Yeung for pure γ-Mn