know somebody/something backwards

know (something) backwards

To be extremely familiar with a particular subject, field, or piece of writing, film, music, etc. Primarily heard in UK. I've read this book so many times, I know it backwards. You should ask Samantha about your car. She knows engines backwards.
See also: backward, know

know something backwards

mainly BRITISH or

know something backwards and forwards

If you know a subject backwards, you know a lot about it. I thoroughly enjoy lecturing and know my subject backwards. He will be very much in demand. He knows the business backwards. They know company personnel policy backwards and forwards.
See also: backward, know, something

know something backwards

be entirely familiar with something.
1991 William Trevor Reading Turgenev People who lived in the town knew it backwards.
See also: backward, know, something

know somebody/something ˈbackwards

(informal, especially British English) know somebody/something extremely well: He must know the play backwards by now — he’s seen it six times!