Fox
In order to make a definitive determination as to which Beverly Hills, 90210 character is most full of shit, I would require the mathematical skills of all NASA's currently laid-off scientists, or, at the very least, a graphing calculator. Most of the time, I call it an eighty-way tie, and yes, that includes Nat. But as soon as Clare Arnold comes onto the scene, she spends all her first season's screen time gunning for that top slot.
Clare, the daughter of California University's Chancellor, comes into Brandon's orbit when Brandon joins "The Task Force," a sketchily defined working group that seems to have been convened for the sole purpose of letting Brandon meet President Clinton (who does appear in the Season 4 finale, but who does not play himself). Clare immediately tries to lock onto Brandon with her sexual tractor beam, not realizing that, at the moment she meets him, Brandon is already juggling two ladies, neither of whom has a chronic Dippity-Do problem. Clare is super-smart, and assumes — wrongly — that since Brandon's on The Task Force, he must be too; between her impression of his intellect and the evidence of her eyes (even I will admit that Brandon's only unattractive once you get to know his personality), she decides that he's the perfect partner for her.
And look, I'll give Clare credit for one thing: for a high-school senior, she has a remarkably strong sense of self — far more than any of the girls in the show's opening-credits cast. She doesn't just speak French to Brandon because she thinks it's seductive; she also does it because she really has lived in France and because she wants to show off her erudition and sophistication. Even though he failed to respond to her overtures at a Task Force retreat, Clare is undeterred, and decides to bring her very best game to Brandon's on a weekend when both their parents are out of town. After explaining her "predicament" (the Chancellor is out of town, and she's clearly skipped out on the friends she's supposed to be staying with), Brandon asks what's in her overnight bag that's made it so heavy, and the real Clare busts out this reply.
"REALLY DECENT LITERATURE"? You think that's what's going to make Brandon tear his pants to shreds to get at you?! Brandon, the braying basketball fan? Brandon, who still routinely calls women "babes"? Brandon, who doesn't realize that his enormous watch makes him look even smaller?
Oh, Clare. You would have been better off spending this weekend reading really decent literature at your own house. You would have gotten a lot further sexually with Lady Chatterley's Lover.