Strong's G57 — ἄγνωστος (adjective)
agnostos (ag'-noce-tos) adj.
1. not known, unknown
2. (mentally) ignorant
3. (figuratively) obscure
[from G1 (as negative particle) and G1110]
KJV: unknown 
Root(s): G1, G1110 
Hebrew root: γνωστός
Occurrences: 1