Ice Queen? (Spoiler)
When the guys are having their testosterone-laden talk in the theater about the various women in the cast and crew, they refer to Sonja as "The Ice Queen" and say that every guy in the cast has tried to get in her pants, but she's unapproachable.
But her character seems to be more like "The Party Girl." She can't wait to get her clothes off with Richard and practically bullies him into casual sex. She sleeps with Orson without a second thought because it's useful to her career. And it's strongly intimated that Selznick is next on her list.
Her dialogs with the lovestruck Richard seem to indicate a cavalier and pragmatic attitude toward flings.
I can think of a lot of slang phrases that might be used in 1937 "boy talk" about a woman with that kind of character, but "Ice Queen" isn't one of them.
I'm not morally judging Sonja, I just think that as an audience, we never see the slightest characterization that would make us think she would have behaved in a way to justify that perception by the guys. So it feels arbitrary and conflicted.