Lazy thief

Another mot from Maigret, from 'Maigret et le Voleur paresseux', from Volume 22 of the collected works.

If one has a spot of the blues, is down in the dumps or having a passing depressing thought, one has a cafard, with the point of interest being that it is also the word for a cockroach. Which I found a striking association.

According to Larousse, cockroaches might also be 'blattes' or 'cancrelats', with the first of these being from the Latin and the second being from the Dutch. While Littré adds the important information that a cancrelat is properly an American cockroach, common in sea ports in Europe. Which name Wikipedia claims misleading, with this particular sort of cockroach actually getting to the Americas from Africa in the seventeenth century, perhaps in the baggage of the slave trade.

So as well as a striking association, another example of the poverty of English in matters animal, with the French offering three words, perhaps each with their own range of meaning, to our one.

PS: I find linguee to be one of the better online dictionaries, with lots of examples of usage, at least on a good day. See reference 1.

Reference 1: https://www.linguee.com/english-french/search?source=auto&query=cafard.