We present limits on spin-independent dark matter-nucleon interactions using
a $10.6$ $\mathrm{g}$ Si athermal phonon detector with a baseline energy
resolution of $σ_E=4.92 \pm 0.01$ $\mathrm{eV}$. This exclusion analysis
sets the most stringent dark matter-nucleon scattering cross-section limits for
dark matter particle masses from $87$ to $140$ $\mathrm{MeV}/c^2$, with a raw
exposure of $9.9$ $\mathrm{g}\cdot\mathrm{d}$ acquired at an above-ground
facility. This work illustrates the scientific potential of detectors with
athermal phonon sensors with eV-scale energy resolution for future dark matter
searches.