Someone who buzzes around you, never stopping their chit-chat even when they are asked to, and although their voice and\or subject of discussion is extremely annoying. Being a mosquito is very common in preteens(especially if those maniacs are fucking gifted), but can be found also in adults.
A girl that wants to date your boyfriend. Although she is not a threat to you, she is annoying and can get under your skin because she will always be buzzing around him. She is generally a girl who always gets what she wants so she isn't shy to flirt with your boyfriend shamelessly even when she knows he is taken. She thinks she can take you down, but like an actual mosquito this girl just needs to be squished.