How to spot an ENEMY?

Not sure if that woman in your social circle is talking you down behind your back? She's likely to be an enemy if she :

• Leaves the room whenever you arrive.
• Often makes sarcastic comments about something you've said.
• Invites everyone in your group except you to a get-together at her place.
• Giggles viciously smile while looking in your direction.
• Never says "hello".
• Plays at not remembering your name - as though you've never met before.
• Avoids eye contact and never smiles at you.
• Has said something very bitchy about you behind your back that has filtered back to you through friends.
• Changes the topic of conversation the millisecond as you come over - as though she has been saying something unkind about you.
• Makes a big show of being talkative to your girlfriends while ignoring you.
• Pretends she doesn't see you if you pass by each other in the shopping mall.