Lots of Unix commands could have had better names :). FWIW, though, the noun form is even less uncommon in languages that borrowed the expression from French.

Lots of Unix commands could have had better names :). FWIW, though, the noun form is even less uncommon in languages that borrowed the expression from French. In my native language (also a Latin language, so borrowing it was straightforward), its use a noun is very limited. Saying that a book is "full of à-propos" (as in "pleine d’à-propos"), for example, wouldn't mean it's apt, or very relevant, it would mean that it's full of subtle, possibly contrarian or lewd motives. That's more or less how it's used in English, too. To non-French speakers -- given when apropos showed up, the Unix audience was very American-centric --, who've only heard it used in the other sense, it actually sounds very appropriate, possibly even more appropriate than about, given how apropos (the program) works.