Not to be confused with the usual "live-action film starring J-pop singers that's not as good as the anime". Yes, there's also a very good anime adapted from the same novel, but:
(a) the film came first (2013 vs. 2016)
(b) this is a serious film with proper actors, including veterans who've been around forever. It's a pleasure to watch them.
(c) it was Japan's submission for the Best Foreign Film Oscar in 2014, although it didn't get shortlisted.
It's about dictionary editors. They edit a dictionary for fifteen years and that's not even a particularly long time. This is only a mid-length one. It's going to be called "The Great Passage" and it's going to be a living dictionary for a modern age, containing all the latest words. (Admittedly these are people you wouldn't expect to know any slang more recent than the 19th century, but that's their goal.) Their office is a snowdrift of word cards, although it eventually turns out that they're not completely without computers.
Our hero is Mitsuya Majime (Ryuhei Matsuda). If the dictionary department is a collection of lovable old fossils, then he's the fossil of fossils. He's a young man, but his communication skills are zero and he's the kind of hopeless case who's only capable of conducting a conversation if it's about word definitions. Put him in front of a pretty girl and he might fall over in shock. (That's not hypothetical. He actually does this.) We first meet him as the world's worst sales representative, but the dictionary department decide that they might have found an ideal recruit.
It's a charming and surprisingly funny film. Majime will make you laugh in little ways, by being Majime. There's one normal human being in the department (Joe Odagiri) and he's funny too. He thinks he's surrounded by weirdos, but he's also capable of quick thinking in emergency situations and the time will come when he'll save the whole project.
It's a hard film to analyse and an impossible one to nitpick, because it's so simple. Editors compile a dictionary. (Imagine trying to pitch that in Hollywood. Go on, imagine.) The story could hardly be more straightforward, although it does have the odd surprise. (Romance for ) The comedy's simple and understated. It's full of old actors, who are all wonderful. I don't think anyone would call this a "THAT WAS BRILLIANT!!!" film and I can see why it was both submitted and rejected for the Best Foreign Film Oscar, but it's nice.