She's definitely an unlikable woman. Ginger from
Casino
is also up there. Even worse, I'd say.

Read through the lists and can't believe no one mentioned Faye Dunaway in Mommie Dearest!
NO MORE WIRE HANGERS!!!!
"I do not like mixing up moralities and mathematics."
Churchill

Well, there is nobody worse than Nurse Ratchet. But here are some pretty vile females.
Olivia DeHaviland - "Hush, Hush Sweet Charlotte"
Joan Crawford - "Harriet Craig"
Maggie Smith - "The Prime of Miss Jean Brodie" (loved it when Pamela Franklin read her beads at the end of the movie)
Bonnie Franklin - "One Day at a Time"
Ruth Roman - "The Baby"
Nancy Allen - "Carrie"
Olivia DeHaviland - "Lady in a Cage"
Kim Stanley - "Frances"
Joan Crawford - "Night Gallery" (wretched person, Joan is terrifyingly good!)
Glenn Close - "Dangerous Liasons"
For those who cited
Bette Davis - "Whatever Happened to Baby Jane?" I can't find Jane Hudson that awful because she made me laugh (a lot), and Bette Davis is just too likeable in general, and because, ultimately, Jane was a very, very sad woman.
Glenn Close - "Fatal Attraction" Alex Forrest was tragic, and I found her extraordinarily sympathetic.
Charlize Theoron - "Monster" same as above, times 10,000
Kathy Bates - "Misery" I liked the movie, but I just couldn't take Kathy Bates very seriously as a villain. To me, she was just sort of grumpy. To be honest, I kind of liked her.
And lots and lots of
scary
females mentioned here, but scary and hateful do not automatically mean the same thing to me.
I thought I was gonna die! - Roseanne Roseannadanna

• Madame de Merteuil in Dangerous Liaisons, Valmont, Cruel Intentions
• Bellatrix LeStrange - Harry Potter
• Umbridge - Harry Potter/Order of the Phoenix
• Baby Jane in Whatever Happened to Baby Jane
• Katherine Parker in Working Girl
• The Mom from Ordinary People

Mo'nique in the movie Precious as Mary.

you're going for, the last ride ah haaaaaaaa

Courtney in Jawbreaker, Kimberly Joyce in Pretty Persuasion and Katherine Merteuil in Cruel Intentions.

I agree, Angela Lansbury in The Manchurian Candidate and also in Gaslight. Fittingly, she was offered the part of Nurse Ratched. Also, don't forget Shirley Stoler in The Honeymoon Killers and Seven Beauties, Lotte Lenya in From Russia with Love and The Roman Spring of Mrs. Stone, Anjanette Comer and Ruth Roman in The Baby or Sonia Dresdel as Mrs. Baines in The Fallen Idol.

Annie Wilkes from Misery
Wicked Witch of the West from The Wizard of Oz
Cruella de Vil from 101 Dalmatians
Lady Tremaine( Cinderlla's Step mom) from Cinderella

The Mother Superior in "The Magdalene Sisters." I loathe her.
Get me a bromide! And put some gin in it!

Most of the females mentioned here PALE in comparison to NR. She is detestable and I can conceive of no physical torture equal to the intense and deep hatred I harbor for her.

Sharon Stone in Casino by far

Glenn Close looked a bit of a dog in that movie, hana

Glenn Close in "Fatal Attraction"
And going back even farther in my memory - Jessica Walter in "Play Misty for Me"

I have 2:
Arnie'n Mom in Christine
and The mom In the original Carrie

Annie Wilkes in Misery
Marquise Isabelle de Merteuil in Dangerous Liaisons
Any of the numerous depictions of Countess Elizabeth Bthory de Ecsed.
The Iron Lady.

Marcia Gay Harden as Mrs. Carmody in "The Mist"

Kathy Bates from Misery played a great villainous. Lady Kaede from Ran is a good one too. If you count animations, I could include Cruella Devill from 101 Dalmatians.

I remember I hated, hated, hated Mildred Pierce's daughter
"Darth Vader is
scary and I
The God
father"

Ginger in Casino. It is mind boggling that Sharon Stone was nominated for an oscar for playing her. There's a really bad woman with no redeeming qualities.
"You want me to roll 6,000 of these!? What? Should I quit my job!?" George Seinfeld

Ellen Page- Hard Candy
Eihi Shiina- Audition
Charlize Theron- Monster
Charlotte Gainsbourg- Antichrist

Also, the strident soprano mistress from CITIZEN KANE and Jaycee from THE LAST PICTURE SHOW.
He didn't get out of the cock-a-doody car!!!

Annie Wilkes in MISERY, Baby Jane Hudson in WHATEVER HAPPENED TO BABY JANE? and Olivia De Haviland's character in HUSH HUSH SWEET CHARLOTTE.
He didn't get out of the cock-a-doody car!!!

Lois from Goodfellas.
I can't stand her.

I'm not being cute, but one might argue Anthony Perkins as Mrs. Bates in Psycho. Even is she was long since dead, the psychiatrist argued that he was keeping her alive and one can argue that Mrs. Bates, NOT Norman, killed Marion, Arbogast, and two other people.