know from nothing

not know from nothing

To be completely ignorant or uninformed (about something). Don't ever second-guess my judgment again, you hear me? You don't know from nothing! Don't mind her, Phil. She doesn't know from nothing.
See also: know, not, nothing
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

know (or not know) from nothing

be totally ignorant, either generally or concerning something in particular. North American informal
See also: know, nothing
Farlex Partner Idioms Dictionary © Farlex 2017
See also: