not know (one) from Adam

not know (one) from Adam

To not know who one is just by looking at them; to have never met someone before. Even though Jake had worked at the company for nearly 10 years, the boss still didn't know him from Adam. I don't blame them for not giving me permission right away. They don't know me from Adam.
See also: Adam, know, not
Farlex Dictionary of Idioms.

not know someone from Adam

Fig. not to know someone by sight at all. I wouldn't recognize John if I saw him up close. I don't know him from Adam. What does she look like? I don't know her from Adam.
See also: Adam, know, not
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

not know someone from Adam

Be unable to recognize someone, as in Although I have worked here for two months, I've never seen the department head; I wouldn't know her from Adam . This term refers to the biblical story about the world's first human being. As at least one writer has pointed out, differentiating someone from Adam makes little sense since he had no name and wore only a fig leaf. [Mid-1800s]
See also: Adam, know, not, someone
The American Heritage® Dictionary of Idioms by Christine Ammer.

not know someone from Adam

If you don't know someone from Adam, you do not know them at all. We have one contact, who is simply a voice on the phone to us. I don't know him from Adam. These people were friends of a friend, who didn't know me from Adam. Note: According to the Bible, Adam was the first human being.
See also: Adam, know, not, someone
Collins COBUILD Idioms Dictionary, 3rd ed.

not know someone from Adam

not know or be completely unable to recognize the person in question. informal
See also: Adam, know, not, someone
Farlex Partner Idioms Dictionary

not know somebody from ˈAdam

(informal) not know who somebody is: This man came into the office and he said that he knew me. I didn’t know him from Adam, which was a bit embarrassing.
See also: Adam, know, not, somebody
Farlex Partner Idioms Dictionary

not know from Adam

See know from Adam.
See also: Adam, know, not
The Dictionary of Clichés by Christine Ammer
See also:
  • not know from Adam
  • not know somebody from Adam
  • not know someone from Adam
  • run with
  • pass (someone or something) off (as something else)
  • pass off
  • reach up to
  • reach up to (someone or something)
  • she's jake
  • not a bother on (someone)