For the novel, please see Rogue (novel).
Rascal redirects here; for the TNG episode, please see Rascals.
"Mister Worf, villains who wear twirl their mustaches are easy to spot. Those who clothe themselves in good deeds are well camouflaged."
– Jean-Luc Picard, 2367 ("The Drumhead")

Rogue was a slang term for a rebellious person, often one with malevolence or ill will. According to Data, additional meanings included: cad, knave, rake, rascal, villain, wild element. (TNG: "The Outrageous Okona")

In space terminology, various astronomical objects not fitting the norm of their nature may be identified as "rogue", such as rogue comets, star clusters, planets or planetoids.

James T. Kirk described Harcourt Fenton Mudd as both a "liar and rogue." (TOS: "I, Mudd")

After witnessing young Jean-Luc Picard's 2327 treatment of Corlina (dating her and Penny at the same time), Q remarked that he didn't know Picard had been such a cad, particularly a male who misused a woman, a fact that impressed him. (TNG: "Tapestry")

In 2365, rascal was one of the terms Data supplied as a synonym for rogue when defining the type of person Thadiun Okona was. Deanna Troi, however, pointed out that unlike the terms he described, Okona had "no malevolence or ill will." (TNG: "The Outrageous Okona")

In 2367, Jean-Luc Picard referred to his friend Louis as "you old rascal". (TNG: "Family")

The Tal Shiar and Obsidian Order's attempt to destroy the Founders' homeworld was painted by Romulan Senate and the Cardassian Union as "a rogue operation." (DS9: "The Die is Cast")