The meaning of the French phrase “bête noire”

I just recently started reading A History of India for a course I’m taking at the university. I came across the expression bête noire in the book, in this sentence:

In this connexion there was another bête noire which cast its shadow on much of the early writing on ancient India.

Having not a clue as to what the phrase meant (other than the fact that noire meant ‘black’), I dutifully looked it up. According to wordreference.com (I currently have no proper French dictionary), I found that it means “peeve” or “pet peeve”.

Having said that, I must say: I find the habit of scholarly writers dropping in random expressions in other languages, without a translation thereof, a bit odd (not to mention rather frustrating at times). If there were a decent reason for using the foreign word, fine - but what was to be gained by the author by using the French version of “pet peeve”? I can obviously understand why there are, for example, many Sanskrit words in the text (usually with a definition or something similar, I might add!) - but French? I don’t see the point.

Literally “bête noire” means “black beast”.

I think scholarly writers write under the assumption that anyone who would read their work would be versed in the language that they use.

As I understand if you read a scholarly work from the 19th century, you’ll find no translations for French, Spanish, Italian, German. As it was assumed, as I said, anyone who would read such a work would know those languages.

Bete noire is from French, but is an English idiom.

In French, a “bête noire” is not something that you hate (as it is used in English), but something that you fear; “en avoir peur comme d’une bête noire”.