rogue
1. An unprincipled, deceitful, and unreliable person; a scoundrel or rascal.
2. One who is playfully mischievous; a scamp.
3. A wandering beggar; a vagrant.
4. A vicious and solitary animal, especially an elephant that has separated itself from its herd.
5. An organism, especially a plant, that shows an undesirable variation from a standard.