This is the 8774th most frequent Japanese word.
本名
Real name.
本名 is used to mean 'real name,' referring to someone's actual name as opposed to a nickname or pseudonym.
彼の本名は知られていない。
His real name is not known.
本名 is used to inquire politely about someone's actual name in a formal context.
本名を教えてもらえますか？
Could you tell me your real name?
本名 refers to someone's personal legal name, contrasting it with an alternate name used professionally or publicly.