Absence of Long-Range V–V Dimer and Magnetic Orderings in High-Entropy (Mg0.2Mn0.2Co0.2Ni0.2Cu0.2)VO₃

V–V dimerization in ilmenite-type vanadium oxides is an intriguing phenomenon that induces structural and metal-to-insulator transitions. Herein, we report the high-pressure synthesis, crystal structure, and electronic and magnetic states of high-entropy ilmenite-type (Mg0.2Mn0.2Co0.2Ni0.2Cu0.2)VO3. Although all the parent ilmenite-type compounds exhibit triclinic (P1̅) symmetry at room temperature, this compound crystallizes in a rhombohedral (R3̅) structure, indicating the absence of long-range V–V dimer ordering. The presence of short-range ordering of the V–V dimer is predicted from the insulating property and crystal structure. Furthermore, magnetic susceptibility and heat capacity measurements revealed multiple-step spin-glass transitions. This study demonstrates that a high-entropy composition hinders electronic (V–V dimer) and magnetic long-range orderings due to local structural distortions and magnetic frustration.