  Using elastic and inelastic neutron scattering techniques, we show that upon
cooling a spatially anisotropic triangular antiferromagnet Ag$_2$MnO$_2$
freezes below $T_f ~\sim 50$ K into short range collinear state. The static
spin correlations are extremely two-dimensional, and the spin fluctuations are
gapless with two characteristic relaxation rates that behave linearly with
temperature.
