From Wiktionary, the free dictionary
Literally, “to be black as in the wolf's lair”.
- IPA(key): /fɛʁ nwaʁ kɔm ʃe lə lu/
faire noir comme chez le loup
- (simile, impersonal) to be dark to the point where one can't see; to be pitch-dark
- Synonym: faire noir comme dans un four