ANONYMOUS

[adjective] - (made or done by someone) with a name which is not known or not made publicThe money was donated by an anonymous benefactor.Police said an anonymous caller warned just after midnight yesterday that a bomb was about to go off.An attempt to implant an embryo using an egg from an anonymous woman donor was unsuccessful.He received an anonymous letter threatening to disclose details of his affair if he didn't pay the money.For reasons of personal safety, the informant wishes to remain anonymous.(figurative) He has a rather anonymous face (= His face is not unusual or different in any way).