rogue

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An unprincipled, deceitful, and unreliable person; a scoundrel or rascal.
• noun One who is playfully mischievous; a scamp.
• noun A wandering beggar; a vagrant.
• noun A vicious and solitary animal, especially an elephant that has separated itself from its herd.
• noun An organism, especially a plant, that shows an undesirable variation from a standard.
• adjective Vicious and solitary. Used of an animal, especially an elephant.
• adjective Large, destructive, and anomalous or unpredictable.
• adjective Operating outside normal or desirable controls.
• intransitive verb To remove (diseased or abnormal specimens) from a group of plants of the same variety.
• intransitive verb To remove diseased or abnormal plants.

from The Century Dictionary.

• To play the rogue; play knavish tricks.
• To wander; tramp; play the vagabond.
• To call (one) a rogue; denounce as a rogue; stigmatize as a cheat or impostor.
• To cheat; injure by roguery.
• To uproot or destroy, as plants which do not conform to a desired standard.
• noun A vagrant; a sturdy beggar; a tramp.
• noun A knave; a dishonest person; a rascal: applied generally to males.
• noun A sly fellow; a wag.
• noun A mischievous or playful person: applied in slight endearment to children or women. Compare roguish, 3.
• noun A rogue elephant (which see, under elephant).
• noun A plant that falls short of a standard required by nurserymen, gardeners, etc.
• noun Synonyms Cheat, sharper, scamp, swindler.
• noun A bait, used in the sardine fishery, consisting of an oily dough made of the roe and entrails of codfish.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb obsolete To give the name or designation of rogue to; to decry.
• transitive verb (Hort.) To destroy (plants that do not come up to a required standard).
• intransitive verb obsolete To wander; to play the vagabond; to play knavish tricks.
• noun (Eng.Law) A vagrant; an idle, sturdy beggar; a vagabond; a tramp.
• noun A deliberately dishonest person; a knave; a cheat.
• noun One who is pleasantly mischievous or frolicsome; hence, often used as a term of endearment.
• noun An elephant that has separated from a herd and roams about alone, in which state it is very savage.
• noun (Hort.) A worthless plant occuring among seedlings of some choice variety.
• noun a collection of portraits of rogues or criminals, for the use of the police authorities.
• noun derisive music performed in driving away a person under popular indignation or official sentence, as when a soldier is drummed out of a regiment.
• noun yarn of a different twist and color from the rest, inserted into the cordage of the British navy, to identify it if stolen, or for the purpose of tracing the maker in case of defect. Different makers are required to use yarns of different colors.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A scoundrel, rascal or unprincipled, deceitful, and unreliable person.
• noun A mischievous scamp.
• noun A vagrant.
• noun Deceitful software pretending to be anti-spyware, but in fact being malicious software itself.
• noun An aggressive animal separate from the herd, especially an elephant.
• noun A plant that shows some undesirable variation.
• adjective of an animal Vicious and solitary.
• adjective by extension Large, destructive and unpredictable.
• adjective by extension Deceitful, unprincipled.
• verb horticulture To cull; to destroy plants not meeting a required standard. Especially when saving seed, rogue or unwanted plants are removed before pollination.
• verb obsolete To give the name or designation of rogue to; to decry.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a deceitful and unreliable scoundrel