whosoever
pron. C2 Proficiency US //ˌhusoʊˈɛvɝ// UK //huːsˌəʊˈɛvɐ// whoso·ev·er
pron. any person who does something. It is a very formal and old-fashioned way to say 'anyone'.
pron. any person who does or is something; used to refer to an indefinite person. Often used in legal or religious contexts to emphasize universality.
Whosoever enters this room must sign the book.
The ancient law stated that whosoever took the throne would be responsible for the safety of the entire kingdom.
The document was signed by whosoever held the title at the time, ensuring that the legal obligations were binding on every subsequent heir.
From Middle English whosoever. By surface analysis, who + so + ever.