What is the full name of St. Agnes?

Her name was Agnes. No surnames were used at the time. The name "Agnes" is actually derived from the feminine Greek adjective "hagn?" (????) meaning "chaste, pure, sacred".

Her name was Agnes. No surnames were used at the time. The name "Agnes" is actually derived from the feminine Greek adjective "hagnē" (ἁγνή) meaning "chaste, pure, sacred".