This doesn't necessarily mean worst acted. Sofia Coppola was terrible in The Godfather Part III, for example, but had the original actress - Winona Ryder - not dropped out, that part wouldn't seem so bad. Some very good actresses made the list (in fact four of them are Oscar winners), but their characters deserve dubious distinction.
*Dishonorable mentions to half the female parts from the Twilight Saga and any movie that starred Elvis Presley or Freddie Prinze Jr.
*Also, Demi Moore's Hester from THE SCARLET LETTER. Completely changed the ending and therefore the point of the story.
10. Bronte (Andie MacDowell), GREEN CARD - An uptight woman really, really wants her greenhouse. And at the last second, for no reason, she says "I don't care about the greenhouse" because she's fallen for the cave troll played by Gerard Depardieu. Probably the least convincing "okay they really love each other" moment in rom-com history.
8. Lucy (Emily Browning), SLEEPING BEAUTY - Nothing much to a character who makes her living by taking knockout drugs and letting creepy rich men do whatever they want to her body while she's out cold.
7. Mrs. Cooper (Mercedes Reuhl), LEADER OF THE BAND - This was a "star" vehicle for Barney Miller's Steve Landesberg, and all there was to Reuhl's character is that she had extreme lust for him the second she laid eyes on him.
6. Lois Lane (Kate Bosworth), SUPERMAN RETURNS - They destroyed Lois by making her a mopey single mom who acts like a corporate lawyer at work.
5. Jennifer (Camille Keaton), I SPIT ON YOUR GRAVE - The ultimate exploitation film (which inexplicably got a remake) about a woman who gets raped by a group of young men, and then raped again, and then again, and then it tries to redeem itself by her getting bloody revenge at the end.
4. Abby (Katherine Heigl), THE UGLY TRUTH - Maybe Heigl thought she was going to get some Apatow karma in this "farce" on romance. In truth, no actress could have made this work, paired opposite a chauvanistic Gerard Butler making her go through a series of humiliating romantic "tests."
3. Amidala/Padme (Natalie Portman), STAR WARS I-III - So let me get this straight. She lives in a society where they elect 14-year-olds to be queen, and those queens have actual power. Ah, but when her term is up, she later gets elected to the more responsible role of senator, but she's too busy going on picnics to fulfill most of her duties, so she lets the single stupidest creature in the galaxy vote on her behalf. Then when she gives birth to her twins, instead of having mama-bear maternal instinct kick in, she dies "of a broken heart."
2. Kate (Eva Longoria), OVER HER DEAD BODY - A woman dies on her wedding day before she can actually exchange vows. She follows her mopey fiance Henry around until he consults a medium named Ashley. Ashley is a fraud, except she can actually see and hear Kate. Ah, but when Ashley starts to fall for Henry, Kate does whatever she can to sabotage it. Like making giant fart noises. She has no curiosity about anything else in the universe or eternity, and no actress on Earth could have saved it.