Noun

1. A scoundrel, rascal or unprincipled, deceitful, and unreliable person.
2. A mischievous scamp.
3. A vagrant.
4. Deceitful software pretending to be anti-spyware, but in fact being malicious software itself.
5. An aggressive animal separate from the herd, especially an elephant.
6. A plant that shows some undesirable variation.
   • 2000 Carol Deppe, Breed Your Own Vegetable Varieties, Totnes: Chelsea Green Pub.

     Maintaining varieties also requires selection, however. It's usually referred to as culling or roguing. ...we examine the [plant] population and eliminate the occasional rogue.

7. An entity set apart from the normal order, which acts in an independent manner. This can apply to individuals, states, or other entities.

Adjective

1. Vicious and solitary.
2. Large, destructive and unpredictable.
3. Deceitful, unprincipled.
   • 2004: Chris Wallace, Character: Profiles in Presidential Courage

     In the minds of Republican hard-liners, the "Silent Majority" of Americans who had elected the President, and even Nixon's two Democrat predecessors, China was a gigantic nuke-wielding rogue state prepared to overrun the free world at any moment.

4. Operating outside of normal controls.

Verb

1. cull, term used by gardeners, especially when saving seed, rogue or unwanted plants are removed before pollination.
   • 2000 Carol Deppe, Breed Your Own Vegetable Varieties, Totnes: Chelsea Green Pub.

     Maintaining varieties also requires selection, however. It's usually referred to as culling or roguing. ...we examine the [plant] population and eliminate the occasional rogue.