inexplainable

It has already been said it was the custom of Deerfoot to follow a certain inexplainable intuition which often came to his help in his moments of doubt.

From Camp-fire and Wigwam by Edward Sylvester Ellis

The third, and to me the most remarkable, class is found not in certain personages or superstitious and determined proceedings, but in sudden and capricious scenes, and in improbable and inexplainable apparitions.

From The Philippine Islands, 1493-1898 - Volume 40 of 55 1690-1691 Explorations by Early Navigators, Descriptions of the Islands and Their Peoples, Their History and Records of the Catholic Missions, as Related in Contemporaneous Books and Manuscripts, Showing the Political, Economic, Commercial and Religious Conditions of Those Islands from Their Earliest Relations with European Nations to the Close of the Nineteenth Century by Emma Helen Blair

He could not account for it, except as he accounted for all inexplainable things, as being the direct prompting of the Great Spirit.

From Camp-fire and Wigwam by Edward Sylvester Ellis

In short, the psychological association of ideas, which we should simply have to accept as inexplainable fact, is thus transformed into a connection which we understand as necessary; and the fact is really explained.

From Psychotherapy by Hugo Münsterberg

On the surface, the announcement appeared significant, but the girl's boldness in coming to her for news was inexplainable to Evelyn.

From Vane of the Timberlands by Harold Bindloss