usually an generic name for an evil twin, as opposed to the good twin. although no one can really be sure which is which. usually refers to the spiteful side of someone.

A pick me is a woman that is willing to do anything for male approval. She will embarrass or throw other women under the bus to achieve this goal. The unfortunate thing about a pick me is usually the men they are trying to seek approval from are of poor quality and treat women badly, leaving little real benefit for the pick me.