What does “tu me gonfles” mean in French?

Gonfler is to inflate: a tyre, a balloon, an air bed. Aimed at a person it means wearing them down, and tu me gonfles is “you’re getting on my nerves.” Ça me gonfle does the same job for a situation. The image is pressure building until something has to give. It is firmly informal but not rude — closer to “you’re a pain” than to swearing.

Watch the adjective, because it points somewhere else entirely: tu es gonflé ! does not mean you are annoying, it means you have got a nerve. Same verb, opposite target, and the two are easy to mix up in a conversation where tempers are already going.