The DUFF? Oh, that’s the “designated ugly fat friend,” of course. Because you thought kids couldn’t be any meaner or adolescence any more difficult. This high-school comedy is far, far kinder, I suspect, than how that disgusting terminology is deployed in the real world, and thank goodness: we need more positive depictions of how to survive the pressures of teendom, and this one ends up in that happy camp. When Bianca (Mae Whitman: The Wind Rises) discovers that she’s the DUFF among her group of friends, she’s informed that she shouldn’t take the description literally and that anyone can be a DUFF… and this revelation is actually plausible, rendering the term more part of a dry taxonomy of high-school hierarchies than a cruel personal putdown. (Hooray for that, because otherwise I would be raging about the ludicrous injustice of cute, funky Bianca being deemed fat and ugly.) As Bianca struggles to figure out who she is and how she fits in, the film avoids the worst clichés of the genre and plays with some others: the inevitable Big Makeover scene, for instance, is all about Bianca refining her own unique style rather than being forced into aping a style that’s wrong for her. And even the clichés that aren’t avoided don’t crash the movie; Bianca’s jock neighbor pal Wesley may be played by an actor (Robbie Amell: Cheaper by the Dozen 2) who is long past high school and looks it, but this isn’t fatal. (Ironically, he and Whitman are the same age — 27 — but she can pass more easily for a teen.) Refreshingly, the movie is savvy about social media, and doesn’t bemoan its existence but recognizes it as simply another vector for pre-existing teenage anxieties and cliquish power struggles to play out along. The DUFF never rises to the sublime wonder of a flick like Clueless, but it resists rather than indulges the worst tendencies of adolescence and trusts kids to basically make the right decisions for themselves. And that’s rare enough for teen movies at the moment.