The French expression Avoir le cafard means to feel low, to be down in the dumps, to be depressed. It literally translates to "to have the cockroach" and is pronounced ah vwar leu kah far. It has an informal register.
The French word cafard, which is probably from Arabic kafr, miscreant, non-believer (according to Le Grand Robert CD-ROM) has several meanings:
- a person who pretends to believe in God
It was the poet, Charles Baudelaire, in Les Fleurs du mal, who first imbued cafard (and also spleen, incidentally) with the fourth meaning. So the French expression avoir le cafard isn't related to cockroaches at all (even though it kind of makes sense-who wouldn't feel bad about having cockroaches?)
In order to use the phrase, you need to conjugate the verb avoir.
- Je ne peux pas me concentrer aujourd'hui - j'ai le cafard.
- I can't concentrate today - I'm depressed.
Le Robert Staff. "Le Grand Robert CD ROM." Edition 1, The Robert, 2004.