Q. A number of educated friends tell me that “sans” is archaic and affected; they
frown when I use it and instead encourage “without.” What do you think?
A. In my opinion, sans cannot be “archaic”: it is the modern French word for “without,”
as I’m sure you know. More than fifty million French people use it every single day, and though some
may say French culture and therefore language is passé, the French would disagree. As for whether “sans”
is affected in English, that’s certainly a matter of personal style. Some would say that any attempt
to use French within English is affected (her hair is the color du jour; I’m applying a sort of faux
finish to this wall). But CMOS, as far as I know, tends not to pass judgment on rhetorical idiosyncrasies, at least those that do not introduce a lack of
clarity.
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]