bad boy

Short definition from Wiktionary

Noun

1. 1
   A man whose rebellious nature makes him dangerous or attractive.
2. 2
   A male criminal.
3. 3
   An undesirable or difficult task.
4. 4
   A powerful or impressive product or item.
5. 5
   Used other than figuratively or idiomatically: see bad, boy.
6. 6
   Alternative spelling of bad boy.