nerve
The French word 'nerf' translates directly to 'nerve' in English. In French, it can be used in the same contexts as in English, such as 'I have a nerve problem' (J'ai un problème de nerf). It can also be used in a figurative sense, such as 'to get on someone's nerves' (taper sur les nerfs de quelqu'un).
He touched the nerve of the question.
This sentence can be used when someone addresses the most critical part or the central issue of a matter, which can frequently present as sensitive, tricky or complex, similar to touching a 'nerve'.
It's the nerve of the war.
This French expression is equivalent to the English saying 'money is the sinews of war'. It means that finance or money is often the crucial or determining factor in conflicts or difficult situations.
I have a pinched nerve in my back.
This phrase is commonly used in a medical context. It refers to a physical condition where a nerve has pressure applied to it, typically resulting in pain, tingling, numbness or weakness.