2. A girl who will do anything for money, or attention.
3. A slut.
2. She is such an entrez, she left me for another guy with more money.
3. That chick is such an entrez!
Assumably the word derived from the French meaning of the word enter, referring to a slut's vagina being entered by many penises.
Another term used is a brushed entrez, which means a slut with cum brushed across her.