INCOGNIZABLE
incognizable, incognoscible
(adjective) incapable of being perceived or known
Source: WordNet® 3.1
Etymology
Adjective
incognizable (comparative more incognizable, superlative most incognizable)
Not cognizable; incapable of being recognised.
Synonyms
• See also incomprehensible
Source: Wiktionary
In*cog"ni*za*ble, a.
Definition: Not cognizable; incapable of being recognized, known, or
distinguished. H. Spenser.
The Lettish race, not a primitive stock of the Slavi, but a distinct
branch, now become incognizable. Tooke.
Source: Webster’s Unabridged Dictionary 1913 Edition