Synonyms of unidentified

2 Syllables

unknown, whatsis

3 Syllables

unsigned, unnamed, so-and-so, such-and-such, unmapped, nameless, uncharted, mysterious, unmarked, unclaimed, undubbed

4 Syllables

unclassified, unfamiliar, anonymous, unexplained, unperceived, unrevealed, unavowed, unattested, pseudonymous, uncredited

5 Syllables

unrecognized, unapprehended, unascertained