bad boy
1. A male, typically a young man, who is or has the image of being a rebel against the established norms of society, and who is often regarded as an icon of sexual attractiveness. Many of the band's fans say Johnny is their favorite because of his image as a bad boy. James Dean was one of the original bad boys of the movie industry, due to his image and film roles as a misunderstood outcast.
2. A task or situation that is tedious, difficult, or undesirable, especially that which is hoped to have a speedy conclusion or resolution. I don't want to be working on this project all night long, so let's just get this bad boy over and done with now.
3. Something that is considered especially impressive, potent, or powerful. My new motorcycle has some real power in the engine; I can't wait to take this bad boy out on the road.