unidentifiedadjective
uk/ˌʌn.aɪˈden.tɪ.faɪd/us/ˌʌn.aɪˈden.t̬ə.faɪd/whose name is not known or is being kept secret:
Police are investigating the death of an unidentified man whose body was found yesterday.
The airline is currently having merger talks with an unidentified rival.
See also
UFO