Idioms are groups of words established by usage as having a meaning which is not deducible from those of the individual words therefore they can be very hard to understand especially out of context. Just like false friends, they can lead to misunderstandings or complete lack of understanding. Online translators such as google translate can only translate literally, so a good old-fashioned dictionary might be more useful for you to deal with idioms. Idioms are fun to learn though, especially when you compare them to your original language.
Here are ten of my favourites:
péter les plombs (to blow one’s top). Here the word plombs refers to the fuses that melt in order to avoid a short circuit.
remonter les bretelles à quelqu’un (to bawl someone out). The image is that of someone shaking someone else violently by their braces.
tailler un costard à quelq’un (to slag someone off). The idea here is that once you have a bad reputation, it is difficult to lose it, in the same way that a suit cannot be altered once it has been cut to a certain shape.
mentir come un arracheur de dents (to be a compulsive liar). In the days before anaesthetic, patients were wise enough not to believe the dentist when he said: “relax, you won’t feel a thing.”
se metre à table (to come clean). This expression dates back to the time when suspects were deliberately starved by police in order to force them to confess. They were given food one they had agreed to confess.
pleurer comme un madeleine (to cry one’s heart out). This expression has nothing to do with the fairy cakes called madeleines but is a biblical allusion to Mary Magdalene, who cried over the body of Christ after his crucifixion.
être dur à la détente (to be slow on the uptake). The image is that of a weapon that is difficult to fire because of a stiff trigger.
filer à l’anglaise (to sneak off, to take French leave). Interestingly but unsurprisingly, the French and English credit each other with this type of rude behaviour!
avoir des oursins dans le porte-monnaie. (to be tight-fisted). Literally “to have sea urchins in one’s purse”. The idea is that someone does not want to put his hand inside his purse because the spikes of the sea urchins might hurt him.
passer l’arme à gauche (to die, snuff off). The expression comes from military terminology, referring to the position in which soldiers hold their weapons when they are at ease. This is because the French expression “to stand at ease” is “être au repos”, which can also mean “to be at rest”, ie dead.
I hope you have enjoyed this little introduction to the world of French idioms. If you want to learn more expressions, you can find more examples in Chambers French Dictionary.