know (someone or something) inside out(redirected from know them inside out)
know (someone or something) inside out
To know everything or nearly about someone or something; to be thoroughly familiar with someone or something. I've read this book so many times that I know it inside out. If you study this material for weeks, you'll know it inside out by the test date. I just think you should know a person inside out before you decide to marry them.
know something inside out
to know something thoroughly; to know about something thoroughly. I know my geometry inside out. I studied and studied for my driver's test until I knew the rules 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.