define beside oneself
English[edit] Possibly derived from Ancient Greek ÏÎ±ÏÎ¬Î½Î¿Î¹Î± â(parÃ¡noia, âmadnessâ), from ÏÎ±ÏÎ¬Î½Î¿Î¿Ï â(parÃ¡noos, âdementedâ), from ÏÎ±ÏÎ¬ â(parÃ¡, âbeyond, besideâ) + Î½ÏÎ¿Ï â(nÃ³os, âmind, spiritâ), with beside mind evolving into beside oneself. beside oneself. (idiomatic) Overcome; consumed by an emotion.