Intellectual property law is very definite on this point. Go read Nolo Press' Copyright Handbook and their trademark book. Billions of dollars get spent tracking and punishing IP theft, that's as real as you get.
Ebooks are intellectual property. To be doubly sure, they are licensed for a single user. It's theft.
If you can't bother to go to a library and check the book out, print or physical? You're saying the rules of society don't apply to you, and are in the social category "criminals, assholes, and people we don't want."
I'm done with this discussion. Have a good day. Don't pirate books.