Spy is one of the best comedies of the year, not just because it's hilarious, but because of what it chooses not to make jokes about.

The new film stars Melissa McCarthy, who is famous for many things: She was nominated for an Oscar for her supporting role in Bridesmaids; she's a boisterously funny and agile comedienne who started with the sketch-and-improv troupe The Groundlings; she stars on the long-running CBS sitcom Mike and Molly; she's been the lead in several feature films, from the hilarious The Heat to the ho-hum, little-loved Tammy and Identity Thief.

But there's at least one more thing McCarthy is well known for: She's overweight.

To her great credit, McCarthy hasn't done much weight-related humor in her films — certainly not as much as Chris Farley in Tommy Boy or Kevin James in Grown Ups. (Though the premise of Mike and Molly is that two fat people fell in love after meeting at Overeaters Anonymous.) But despite the relative restraint of McCarthy's films, loudmouth semi-critics like Rex Reed and Jeffrey Wells have famously used them as a jumping-off point for mean-spirited remarks about her appearance.

We've been conditioned to expect, consciously or not, that when a plus-sized person has the leading role in a comedy, there are going to be fat jokes. Many people surely assume that Spy, an espionage comedy starring McCarthy, is full of fat jokes. But here's the thing: Spy contains not a single joke about Melissa McCarthy's weight. Not one. Not only are there no jokes about it, nobody even refers to it, nor mentions it, nor seems to notice it. A thin actress could have played the role without having to revise any of the script.

Writer-director Paul Feig, who worked with McCarthy on Bridesmaids and The Heat, thought scheduling issues would prevent her from being in Spy, so he wrote the part without anyone specific in mind. He went back to make changes when McCarthy came aboard, but as he told RogerEbert.com's Peter Sobczynski, "There was not that much of an adjustment, because it was really about an Everywoman who gets put in extraordinary circumstances."

Which isn't to say McCarthy's character isn't the butt of jokes. She is; they're just not about her weight. McCarthy plays Susan Cooper, a C.I.A. analyst who's given a field assignment when all the other agents' identities are compromised. She's initially timid and unconfident, a dowdy nobody. The cover identities she's given cast her as a cat lady, a divorced mom, and a Mary Kay salesperson, all lending themselves to frumpy, unflattering disguises that stand out even more when she goes to fancy places like Paris and Rome. People make fun of that — of her apparent lack of sophistication, her unfashionableness, her plainness. But nobody ever so much as implies that her girth is a factor in their ridicule. (And as Susan gradually gets comfortable in her new role, she starts dishing out the insults as fast as she receives them. No doormat, she.)

This clearly intentional decision not to do any fat jokes means finding more creative, smarter, and more progressive ways to get laughs. There's an extraordinary moment when Susan bickers with Rick Ford (Jason Statham), a real C.I.A. spy who's outraged that they've sent a "secretary" to do his job. She has to get close to a male target, and Ford is incredulous.

"Are you gonna seduce him? Is that your big f---ing plan?" he says.

"Yeah, what if it is?" she fires back. "Why is that so hard to believe?!"

"Because you look like a flute player in a wedding band, that's f---ing why."

It's a crack about her outfit and hairstyle, which are elegant for her but not fashionable enough for the wealthy high-rollers she's after, and not directly about her weight. It's classy. That's an odd thing to say about a film as cheerfully vulgar as this one, but here we are.

There's another impressively progressive aspect of Spy: The key roles — the spy, her best friend, her boss, and the villain — are all women. What's more, nothing is done to draw attention to this fact. The movie is full of female empowerment (in the end Susan would rather hang out with her gal pal than hook up with the hunky male spy) without ever being "about" feminism.

When people talk about wanting diversity in movies without the movies being heavy-handed or self-congratulatory about it, Spy is the kind of movie they're talking about. It stands on its own as a funny action comedy, and it does that without being sexist or size-ist. Bravo.