unknown person; anonymous individual
Refers to a person whose name is not known or not disclosed. Often used in formal or written contexts.
The letter came from an unknown person.
The donor field was listed as 'anonymous'.
名無し is a casual term for 'nameless' or 'anonymous', often used online. 失名氏 is more formal and typically used in official or written contexts.
Compound of 失 (lose, miss) + 名 (name) + 氏 (honorific suffix for a person). The exact historical derivation is uncertain, but the term is used to refer to an unnamed or unknown person in formal writing.