неизвестен означава в английски

indecisive▼(inconclusive or uncertain)
adjective
[UK: ˌɪn.dɪ.ˈsaɪ.sɪv] [US: ˌɪn.də.ˈsaɪ.sɪv]

obscure▼(not well-known)
adjective
[UK: əb.ˈskjʊə(r)] [US: əb.ˈskjʊr]

unknown▼(not known)
adjective
[UK: ˌʌn.ˈnəʊn] [US: ənˈnoʊn]