  A spin-1/2 triangular-lattice antiferromagnet is a prototypical frustrated
quantum magnet, which exhibits remarkable quantum many-body effects that arise
from the synergy between geometric spin frustration and quantum fluctuations.
It can host quantum frustrated magnetic topological phenomena like quantum spin
liquid (QSL) states, highlighted by the presence of fractionalized
quasiparticles within a continuum of magnetic excitations. In this work, we use
neutron scattering to study CoZnMo$_3$O$_8$, which has a triangular lattice of
Jeff = 1/2 Co2+ ions with octahedral coordination. We found a
wave-vector-dependent excitation continuum at low energy that disappears with
increasing temperature. Although these excitations are reminiscent of a spin
excitation continuum in a QSL state, their presence in CoZnMo$_3$O$_8$
originates from magnetic intersite disorder-induced dynamic spin states with
peculiar excitations. Our results, therefore, give direct experimental evidence
for the presence of a disorder-induced spin excitation continuum.
