The Collaborative International Dictionary
Unsearchable \Un*search"a*ble\, a. Not searchable; inscrutable; hidden; mysterious.
The counsels of God are to us unsearchable.
--Rogers.
[1913 Webster] -- Un*search"a*ble*ness, n. --
Un*search"a*bly, adv.
Douglas Harper's Etymology Dictionary
late 14c., from un- (1) "not" + searchable (adj.).
Wiktionary
a. 1 That cannot be investigated or searched into; unknowable, inscrutable. 2 That cannot be sought out or looked for. 3 (context computing English) Not capable of being searched; on which one cannot perform a search.
Usage examples of "unsearchable".
And, then, in all that universe of things that fills that bottomless pit and shoreless sea the human heart, there is nothing deeper down in it than just its deep and unsearchable atheism.
By this also I have learned to dread Thine unsearchable judgment, who afflictest the just with the wicked, but not without equity and justice.