The word "screwball" sounds like a horrendous-but-campy insult; like something your grandma would call your great uncle after drinking a few too many eggnogs at a holiday party.
But it's actually a totally benign term, for a totally benign (although hilarious) kind of film.
Screwball comedies flourished during the Great Depression. They're a lot like romantic comedies; there's a guy, there's a girl, and they fall in love while saying witty things. But screwball comedies were…well, screwier.
They have fast-paced dialogue; they have slam-bang humor. And most of all the romances are not just romances, but struggles for dominance. The guy plots to get the girl or, in a role reversal for films of the time, the girl plots to get the guy.
Screwball comedies like His Girl Friday also often addressed the changing role of women—or at least the nervousness around the changing role of women. There's a big question beneath all that yacking: can you still have love and romance with a working woman who would rather outwit you than darn your socks.
And His Girl Friday answers by saying: of course. In this film, a career is a way to a woman's heart. If you tell her "The movies will be after you! There'll be a Hildy cigar!" and she'll fall into your arms… even if—or especially because—she calls you a "stinker".
This film is one the most famous screwball comedies around—and one of the other contenders for Best Screwball Comedy is another Howard Hawks/Cary Grant effort, Bringing Up Baby (1938).
But other notable screwball comedies are The Awful Truth (1937), also with Cary Grant (he was screwball's leading man), and It Happened One Night (1934).
Oh, and we can't forget The Philadelphia Story (1940). You know who The Philadelphia Story stars? Cary Grant (as Hildy discovers, you can't escape him).