person of unknown background; suspicious stranger
Derogatory set phrase used to dismiss someone as a nobody from an unknown or untrustworthy background. Often used in the pattern どこの馬の骨かわからない.
Don't let someone you don't know from Adam into your house.
She must be crazy to marry a man who's a complete nobody.
Also means a person of unknown identity, but is less derogatory and more like 'John Doe' or an anonymous person.
An adjective phrase meaning 'of unknown character' or 'suspicious', used more broadly for things and situations, not just people.
Standard kanji-kana mixed spelling.
Full kanji spelling; rarely used in modern writing.
Literally 'a horse bone from somewhere', implying a worthless or unknown origin. The exact origin is uncertain, but it likely arose as a colorful derogatory expression in colloquial Japanese.