What is the ruling on backbiting someone who does not pray if they wrong me or someone I love, and what is the ruling on saying "So-and-so is a hypocrite" when one is certain of her hypocrisy, her not praying, and her lying?

If a woman abandons prayer, is hypocritical, unjust, and a liar, she is in grave danger, and at the very least, she is a transgressor (fasiq). It is permissible to backbite a transgressor concerning the sins they openly commit, and open sinning means displaying them without concealment. Whoever has two faces is a hypocrite, and it is permissible to describe them as such.