Here's a case of arrested development: Guy Trilby, 40, is a stunted man-child who finds a legal loophole allowing him to enter a national middle-school spelling bee.

Jason Bateman gives Guy a decidedly cutthroat, antisocial spin. Bateman is great playing beleaguered, reasonable Everymen, but he's a virtuoso at smug jerkwads, and in "Bad Words" he has his Iago. Guy combines the killer instinct of a schoolyard Stalin with peerless one-upmanship and sabotage skills.

When Guy strikes, he draws blood. The trick he pulls on a pubescent female competitor, involving a ketchup packet and khaki pants, is one of the grossest practical jokes since Cameron Diaz borrowed Ben Stiller's hair gel. Good luck spelling onomatopoeia after that, little girl.

While "Bad Words" is only sporadically funny, Bateman throws himself into the role without shame or ego. The film is also his directing debut, and a very capable one. He never sentimentalizes Guy nor soft-pedals his cruelty. The back story of his anger explains him (implausibly, it must be said), but doesn't excuse him. Not since W.C. Fields allowed that he likes children — if you parboil them first — has there been a comedic enemy of kids this incorrigible.

Naturally, parents of the young participants are irate. Allison Janney plays a contest administrator determined to disqualify Guy by fair means or foul, while the bee's founder, Philip Baker Hall, looks on like a disappointed walnut. Kathryn Hahn plays an online journalist following Guy's story. The part exists to enable exposition dumps and to give Guy an age-appropriate romantic foil. A movie with angry, subversive Guy entirely surrounded by tadpoles would be too creepy to contemplate.

Guy does strike up a rapport with a 10-year-old Indian-American contestant played guilelessly by Rohan Chand. Guy dubs him Slumdog, teaches him the joys of foul language, and shows the boy a sight or two that probably gave the ratings board indigestion.

There may be some subset of the audience that is nostalgic for the old bloodsport traditions, before the political-correctness crowd imposed its anti-bullying agenda. Watching Guy fillet his little rivals may remind them of the good old days, when middle school was such a social/hormonal chamber of horrors that no amount of supervision could mitigate the agony.

I'm not sure I'd endorse that, but I did appreciate the decision not to end on a note of healing therapy. Bateman aims the movie at a specific tone of nasty humor and he never backs off. It may not be a wise decision, but it shows nerve.