Meaning
To have no idea who someone is; to be completely unable to identify or recognize a person. It usually emphasizes that the person is a total stranger to the speaker. Informal and colloquial; entirely neutral despite the biblical reference. Regional use: General English.
Origin
The phrase alludes to Adam, the first human in the biblical book of Genesis, on the logic that no one living could claim to recognize him, so someone you 'do not know from Adam' is utterly unfamiliar. Etymonline records the expression by 1784, and extended forms such as 'not know someone from Adam's off ox' appeared by 1880. Dictionary.com's usage examples show the idiom well established in 19th-century fiction, including novels by Trollope.
Research Sources
References used to check this entry’s meaning, history, or documented forms.
Variants
- don't know her from Adam
- not know someone from Adam's off ox
- wouldn't know him from Adam
Usage Examples
- A man I didn't know from Adam waved at me across the parking lot, and it took a moment to place his face.
- The recruiter called about a company I didn't know from Adam, so I did some research before replying.
- She wouldn't know her second cousins from Adam, having never attended a single family reunion.