“David sees an aspect of my personality, a fierceness, that he wants to exploit,” Amy Adams, 39, says of David O. Russell, her American Hustle director. “I remember when we were doing The Fighter, he saw it and was like, ‘I want to figure out what that is.'” Well, figure it out he did. Sydney Prosser is the most ferocious creature the actress (who in 2013 also appeared in Man of Steel and Spike Jonze’s Her) has ever portrayed. As partner and mistress to Irving Rosenfeld (Christian Bale), Sydney is a stripper-turned-con woman posing as a British aristocrat. She’s a master of keeping her emotions hidden — using clingy dresses and plunging necklines to distraction — but Adams allows us to see not just a hustler’s steely resolve but also her longing and sadness. When Sydney faces down Irving’s loose cannon of a wife (Jennifer Lawrence) in an Atlantic City bathroom, it has the heightened tension of a prizefight, a spectacular showdown that ends with Lawrence planting a hostile kiss on Adams’ lips — an Adams suggestion. “David always said that Sydney was a weapon,” she says. And Adams has proved herself to be an expert sniper.