I need to know the name of a movie.

I think it might be late 80's, early 90's.

There's this woman, and she's either girl #1's best friend, or she just became Girl #1's roommate, or something I don't know. The roommate bit sounds more like it. Girl #2 starts to copy Girl #1 in everything. Clothes, hair, job, tries to steal her husband, and evetually tries to kill Girl #1. I think she pushes her off something, in the basement, maybe.

The scene I remember the most is when Girl # 2 drops a glass onto Girl #1's body after pushing her down (into the basement?). She says a line and walks off.

I think it's called _____ Woman or Woman ______. But I'm not sure.

This sounds quite a bit like Single White Female.
Bridget Fonda's character is looking for a roommate and comes across Jennifer Jason Leigh's character, who eventually tries to become her. She cuts & dyes her hair the same, kills Bridget Fonda's dog as well as her boyfriend, and then tries to kill her, too.
Hope this helps you!