From Wiktionary, the free dictionary
Literally, “to rain like a pissing cow”.
- IPA(key): /plø.vwaʁ kɔm vaʃ ki pis/
pleuvoir comme vache qui pisse
- (simile, vulgar) to rain like a cow pissing on a flat rock, to piss it down
- Synonym: (informal, not vulgar) pleuvoir des cordes