How well I remember this word from the French Foreign Legion stories in series that started
with "Beau Geste". The legionnaires, in remote desert outposts, developing minor mental
disturbances because of boredom.
cafard
n.
5Fr, low spirits, cockroach, orig., hypocrite, altered (with pejorative 3ard) < MFr caphars < Ar kafir, hypocrite, lit., infidel: see KAFFIR6 boredom, melancholy, listlessness, etc.