Synonyms of undiscovered

2 Syllables
unknown, unseen
3 Syllables
unbeknownst, so-and-so, such-and-such, curtained, unmapped, remotest, uncharted, obscure, remoter, unheard-of, little-known
4 Syllables
unremarked, unrenowned, unfamiliar, unobserved, unexplained, untraveled, unexplored, unperceived, unnoticed, undetected, god-knows-where, unexposed
5 Syllables
unapprehended, unascertained