↑ 1988, 国語大辞典（新装版） (Kokugo Dai Jiten, Revised Edition) (in Japanese), Tōkyō: Shogakukan
Etymology
Compound of 御(o, honorific prefix) +任せ(makase), the 連用形(ren'yōkei, “stem form”) of verb 任せる(makaseru, “to entrust with something or someone, to leave (up) to something or someone”), itself the causative form of Old Japanese verb 任く(maku, “to order someone to do something; to appoint someone to a role or responsibility”).[1]