not know (one) from a can of paint(redirected from didn't know one from a can of paint)
not know (one) from a can of paint
To not know who one is just by looking at them; to have never met one before. Even though Jake had worked at the company for nearly 10 years, the boss still didn't know him from a can of paint. I don't blame them for not giving me permission right away. They don't know me from a can of paint.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.