know something/someone inside out

know something/someone inside out

COMMON If you know something or someone inside out, you know them extremely well. Liam has played for some of the greatest clubs in Europe and knows the game inside out. I used to think I knew my daughter inside out, and I still find it hard to understand what she has done to me. Note: You can also say that you know someone or something inside and out. He knows the house inside and out, having stayed there so often.
See also: inside, know, out, something