空梅雨 (karatsuyu: unusually dry rainy season) empty + plum + rain
One dictionary unhelpfully defines 空梅雨 as “rainless tsuyu.” What’s a tsuyu? Breaking down as plum + rain, it turns out to mean “rainy season.”
Putting that strangeness aside, I’m left wondering how to define 空 in 空梅雨. Surely, it’s not “rainless.” And “empty” isn’t quite right. If anything, this 空 seems to be functioning like 無 or 不, the prefixes meaning “no” or “not.” But 空 can’t take on that role; nothing supports that. It might mean “void of content” here, but it’s hard to be sure.
The situation makes more sense when one learns that karatsuyu can also be written as 乾梅雨. In that compound, the first kanji means “dry.” Perhaps 乾梅雨 was the original way of writing karatsuyu.