Evidence for multiple magnetic transitions and unconventional spin exchange interactions in the ilmenite insulator ${\mathrm{MnTiO}}_3$ is provided via neutron scattering. On cooling, while G-type antiferromagnetic (AFM) order sets in first at 63 K with a $k_1=\left(000\right)$ characteristic wave vector, a weaker second magnetic transition with $k_2=\left(00\frac{3}{2}\right)$ appears near 42 K, giving rise to a noncollinear structure. Intrinsic buckling of the honeycomb lattice along $\mathit{c}$ creates bond anisotropy and a distorted crystal field that can lead to exchange paths that modulate orbital overlap and spin-orbit coupling. The inelastic spectrum is best described by magnetic exchange anisotropy that breaks the local symmetry of the honeycomb, with competing AFM Heisenberg, Dzyaloshinskii-Moriya, and alternate intraplanar ferromagnetic interactions, that may yield a weakly coupled ladder system.

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• Antiferromagnetism
• Magnetic order
• Magnetism
• Antiferromagnets
• Honeycomb lattice
• Neutron scattering