know somebody/something inside out

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.
See also: inside, know, out

know somebody/something inside ˈout

(informal) know somebody/something very well: You’ve read that book so often that you must know it inside out by now.She knows me inside out. I can’t hide anything from her.