  CePdAl is a prototypical frustrated Kondo lattice with partial long-range
order (LRO) at $T_\mathrm{N}=2.7$ K. Previous bulk experiments under
hydrostatic pressure found signatures for a quantum critical regime that
extends from $p_\mathrm{c} \approx 0.9$ GPa, where LRO disappears, up to $\sim
1.7$ GPa. We employed extensive muon spin relaxation and rotation ($\mu$SR)
experiments under pressure. The continuous and complete suppression of LRO at
$p_\mathrm{c}$ is confirmed. Above $T_\mathrm{N}(p)$ and beyond $p_\mathrm{c}$,
an additional crossover scale $T^\ast(p)$ characterizes the change from pure to
stretched exponential relaxation in zero field. Remarkably $T^\ast(p)$ agrees
with previously determined signatures of entropy accumulation above LRO. This
coincidence microscopically evidences fluctuating frustrated spins at $T\leq
T^\ast$ with spin-liquid behavior. Power-law divergences of the temperature and
longitudinal field dependences of the relaxation rate, with time-field scaling,
at pressures between $p_c$ and 1.7 GPa characterize this regime as quantum
critical.
