so-and-so; a certain person
Used as a placeholder for an unspecified or intentionally concealed person's name, similar to 'Mr. X' or 'so-and-so'. Often appears in formal or written contexts.
The contract listed the name as 'so-and-so'.
A certain person (Mr. So-and-so) assumed the post.
Kana spelling is sometimes used for clarity or in informal writing.
Variant kanji form; less common than 某々.
Reduplication of 某 (ぼう, 'a certain person'), used as a placeholder name. The exact historical derivation is uncertain, but the form is conventionally associated with concealing or generalizing a person's identity.