In slang, a troll is a person who posts or makes inflammatory, insincere, digressive, extraneous, or off-topic messages online (such as in social media, a newsgroup, a forum, a chat room, an online video game) or in real life, with the intent of provoking others into displaying emotional responses, or manipulating others' perception, thus acting as a bully or a provocateur. The behavior is typically for the troll's amusement, or to achieve a specific result such as disrupting a rival's online activities or purposefully causing confusion or harm to other people.
In this context, both the noun and the verb forms of "troll" are frequently associated with Internet discourse. Media attention in recent years has equated trolling with online harassment. The Courier-Mail and The Today Show have used "troll" to mean "a person who defaces Internet tribute sites with the aim of causing grief to families". In addition, depictions of trolling have been included in popular fictional works, such as the HBO television program The Newsroom, in which a main character encounters harassing persons online and tries to infiltrate their circles by posting negative sexual comments.
Application of the term troll is subjective. Some readers may characterize a post as trolling, while others may regard the same post as a legitimate contribution to the discussion, even if controversial. More potent acts of trolling are blatant harassment or off-topic banter. However, the term Internet troll has also been applied to information warfare, hate speech, and even political activism.
The "Trollface" is an image occasionally used to indicate trolling in Internet culture.
At times, the word is incorrectly used to refer to anyone with controversial, or differing, opinions. Such usage goes against the ordinary meaning of troll in multiple ways. While psychologists have determined that psychopathological sadism, dark triad, and dark tetrad personality traits are common among Internet trolls, some observers claim that trolls do not actually believe the controversial views they claim.