know through and through

know (someone or something) through and through

To have a thorough and complete knowledge of someone or something. I know Elizabeth through and through, so I really doubt that she's hiding something. A: "You can recite that poem from memory?" B: "Sure, I know it through and through."
See also: and, know, through
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

know something through and through

to know something very well. I want you to know this project through and through before the staff meeting. I know my part in the play through and through.
See also: and, know, through
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
See also: