undiscoverably

His obstinate and tremendous spirit was now withdrawn somewhere, into some fastness more recondite than sleep; not far off; not detached, not dethroned; but undiscoverably hidden, and beyond any summons.

Clayhanger Arnold Bennett 1899

There is no public man -- have no fear, my dear Home Secretary -- I have not planned to assassinate secretly, mysteriously, unintelligibly, undiscoverably.

The Grey Wig: Stories and Novelettes Israel Zangwill 1895

There is no public man -- have no fear, my dear Home Secretary -- I have not planned to assassinate secretly, mysteriously, unintelligibly, undiscoverably.

The Big Bow Mystery Israel Zangwill 1895

There was at any rate nothing scant either in her admissions or her perversions, the mixture of her fear of what Maisie might undiscoverably think and of the support she at the same time gathered from a necessity of selfishness and a habit of brutality.

What Maisie Knew Henry James 1879

Mr. Wilding, falling back into his former perplexity, tried once more to recover that lost recollection, associated so closely, and yet so undiscoverably, with his new housekeeper's voice and manner.

No Thoroughfare Charles Dickens 1841

_ These regular times are no doubt the most important fundamental entities of it, and may even lie undiscoverably at the root of all varieties of rhythm whatsoever, and further they may be the only possible or permissible rhythms for a modern composer to use, but yet the absolute dominion which they now enjoy over all music lies rather in their practical necessity and convenience (since it is only by attending to them that the elaboration of modern harmonic music is possible), than in the undesirability (in itself) or unmusical character of melody which ignores them.

A Practical Discourse on Some Principles of Hymn-Singing Robert Seymour Bridges 1887

Mr. Wilding, falling back into his former perplexity, tried once more to recover that lost recollection, associated so closely, and yet so undiscoverably, with his new housekeeper’s voice and manner.

No Thoroughfare 2007

a break, without a jar, softer than sleep and as continuous, gayer than the rainbow and as undiscoverably connected with any obvious cause.

A History of Elizabethan Literature George Saintsbury 1889