Definition of "unsearchable"

He chastiseth and corrects, as to Him seems best, in His deep, unsearchable, and secret judgment, and all for our good.

1624, Democritus Junior [pseudonym; Robert Burton], The Anatomy of Melancholy: […], 2nd edition, Oxford, Oxfordshire: Printed by John Lichfield and James Short, for Henry Cripps, partition II, section 3, member 3

Preachers warned […] that although God might sometimes make the meaning of his judgements clear they were normally unsearchable.

1971, Keith Thomas, Religion and the Decline of Magic, Folio Society, published 2012, page 103

“Having a band name like that makes me totally unsearchable,” says Rhode Island artist Λ, explaining that his name is pronounced “arc”, “but I like how using symbols means favouring an aesthetic choice over a more practical one. […] ”

2010 August 11, Sian Rowe, quoting Λ, “Meet the bands whose /\/ /\ /\/\ € $ are made out of $¥ /\/\ ß 0 \ $”, in The Guardian‎

That there should be two unsearchables in the universe, that God should be one and man the other, would confer great dignity and honour upon us men were it not for the humiliating fact that it is our deceitfulness that renders us an inscrutable problem to all but God.

1887, Richard Roberts, My later ministry: being sermons, &c., page 82