Noyer le poisson

Literally: To drown the fish

Example: “Quand je lui ai demandé où était l'argent, il a noyé le poisson en parlant de la météo.” — When I asked him where the money was, he dodged the question by talking about the weather.

English equivalent: To muddy the waters

Origin: The modern sense — to bury an awkward question under a flood of irrelevant talk — is from the 1930s, but fishermen were using the phrase from the end of the 19th century for something entirely literal: once a fish was hooked, pulling it in and out of the water repeatedly wore it down before it was landed, which is also a fair description of exhausting an opponent with a question by dunking it in irrelevance over and over. A rival theory points to fishmongers reviving a tired or damaged fish's appearance by churning it in a tub of water so the motion made it look alive to a buyer — deceit rather than exhaustion, but the same act of drowning something in water to hide its true state.