a certain person; a certain amount
A set phrase used to refer vaguely to an unspecified person or amount, often with a dismissive or humble tone. The meaning depends on context: when referring to a person, it implies 'somebody or other'; when referring to an amount, it implies 'some amount or other'. The phrase is somewhat old-fashioned and literary.
Somebody or other came to visit, but I missed asking their name.
I heard he donated some amount of money or other.
Standard kanji spelling for this set phrase.
Mixed kanji-kana spelling; less common but still encountered.
The phrase combines 何の (what kind of) with 某 (a certain person/amount), forming a literary expression for an unspecified person or amount. The exact historical derivation is uncertain.