With Mark Liberman gone fishin' to Japan, and knowing the trouble LanguageLoggers are likely to get into
in exotic foreign places (see Geoff Pullum's
postcard from Vegas),
my thoughts naturally turned to venereal disease.
The Japanese word for "syphillis" [baidoku] is written 梅毒. 梅 is "plum", as an independent word given its native Japanese reading [ume],
and 毒 is "poison". You might wonder what syphillis
has to do with plums. The answer is: nothing. The original way of writing
[baidoku] is 黴毒, where 黴
means "must, mildew". As a separate word it is given the native Japanese reading [kabi].
"mildew poison" makes a lot more sense. 黴 is a complicated
character, requiring 23 brush strokes, and isn't all that commonly used. In fact, it isn't
on the Ministry of Education list of characters approved for official use. So it was replaced
in common usage by the homophonous 梅, a common character requiring only 10 or 11 strokes depending on which variant you use. Such
replacements of a character by a different character having the same sound are
called 当て字 [ateji].