1º_ Producing a sound by vibration is typical of that generated by flying insects with the rapid movement of their wings. It's an onomatopoeia mimicking that sound. 2º_ To be or pass near something. It is also an analogy with the buzzing of insects such as the mosquito, which is clearly heard as you pass by. 3rd_ To expel and to leave quickly. It's because of the expression "to go buzzing". 4th_ Strike a blow.