Two-dimensional honeycomb lattices, characterized by their low coordination numbers, provide a fertile platform for exploring various quantum phenomena due to the intricate interplay between competing magnetic interactions, spin-orbit coupling, and crystal electric fields. Beyond the widely studied $J_{\mathrm{eff}}=1/2$ honeycomb systems, $S=3/2$ honeycomb lattices offer a promising alternative route for exploring spin-$S$ Kitaev models and the effects of bond disorder. Herein, we present crystal structure, thermodynamic, neutron diffraction, and muon spin relaxation ($\mu \mathrm{SR}$) measurements, complemented by density functional theory (DFT) calculations on an unexplored $3d$ transition-metal-based compound ${\mathrm{Co}}_2{\mathrm{Te}}_3{\mathrm{O}}_8$, where ${\mathrm{Co}}^{2+}$ ($S=3/2$) ions form a distorted honeycomb lattice in the crystallographic $bc$ plane without any antisite disorder between constituent atoms. A clear $\lambda$-type anomaly around $T_{\mathrm{N}}\approx 55\mathrm{K}$ in both magnetic susceptibility and specific heat data indicates the onset of a long-range ordered state below 55 K. The dominant antiferromagnetic interaction between $S=3/2$ moments is evidenced by a relatively large negative Curie-Weiss temperature (${\theta }_{\mathrm{CW}}=-103\mathrm{K}$) derived from magnetic susceptibility data and supported by DFT calculations. The signature of long-range antiferomagnetic order state in the thermodynamic data is corroborated by neutron diffraction and $\mu \mathrm{SR}$ results. Furthermore, $\mu \mathrm{SR}$ experiments reveal the coexistence of static and dynamic local magnetic fields below $T_{\mathrm{N}}$, along with a complex magnetic structure that can be associated with $\mathit{XY}$-like antiferromagnet, as confirmed by neutron diffraction experiments.

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• Frustrated magnetism
• Magnetic susceptibility
• Magnetism
• Specific heat
• Muon spin relaxation & rotation