While driving: constantly
changing lanes and passing in between cars, most often at a high speed and in a dangerous manner (e.g. no
blinkers). Someone who is weaving basically wants to overtake EVERYONE on the road, both on their lane and others. Almost exclusively met when multiple lanes are going in the same direction, especially on highways.
Etymology: the word comes from the motion of changing lanes from left to right and left again (like in a
sine wave flipped on its side), which is similar to the motion when weaving clothes (you pass your thread and needle under another thread, then go up and pass over the next thread, go under the next one, and so on and so forth).