not know (someone) from a bar of soap

not know (someone) from a bar of soap

To be completely unaware of or know nothing about someone; to have never met the person indicated. My girlfriend got really excited when a movie star apparently walked past us, but I wouldn't know him from a bar of soap. Someone I wouldn't know from a bar of soap just contacted me online, claiming to be a distant relative.
See also: bar, know, not, of, soap
Farlex Dictionary of Idioms.
See also:
  • have no idea
  • not have the first idea
  • girlfriend
  • be wild about (someone or something)
  • none the wiser
  • not have the slightest idea
  • unknown to (one)
  • unknown to somebody
  • unbeknownst to (one)
  • unbeknown to (one)