Penemy
Someone who feigns friendly with someone, then writes (generally in an online forum such as Facebook or a personal blog) disparaging remarks about that person. Journalists are prime culprits in this matter.
1) "The guy was really great during our interview; he asked me about my musical influences and how the tour is going. Then I read this stupid thing on his blog about how fat I look onstage. I have a new penemy."
2) "Jess was all sweet to me all week. Then Jenn ask me 'did you see what she said about you on Facebook? Oh, maybe she posted it private...' Anyway, I hate that bitch, she's such a penemy."
2) "Jess was all sweet to me all week. Then Jenn ask me 'did you see what she said about you on Facebook? Oh, maybe she posted it private...' Anyway, I hate that bitch, she's such a penemy."