You pronounce it:
1. fine; completely satisfactory; OK.
I read it while reading The Brief Wondrous Life of Oscar Wao by Junot Diaz:
To my virginity! Oscar shouted.
Oscar, cool it, bro. People don’t want to hear about all that.
You’re right, they just want to stare at me.
Come on, tranquilize.
He slumped. I’m copacetic.
You ain’t pathetic.
I said copacetic. Everybody, he shook his head, misapprehends me. (189)
***Note: this book is one well written book, but a bit intense if you don’t like cussing and description of body parts. I also enjoyed Zadie Smith’s other two, but this one is also great. Certainly, very vulgar, but well written. I don’t think I would normally decide upon this book if it weren’t a requirement for class, due to how vulgar it is. I believe the professor mentioned it is #1 on the best books of the millennium in the English language.