1- A cock sucking man or woman who fucks a mother of some kind.
2- a name used by people who are mad at some other mother fucking cock sucker.

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.

(n.) a derogitary term used for a noun

also see jackass,bitch,fucker,hoe, and various other forms of profanity.