Rudeness (also called impudence or effrontery) is the disrespect and failure to behave within the context of a society or a group of people's social laws or etiquette. These laws have already unspokenly been established as the essential boundaries of normally accepted behaviour. To be unable or unwilling to align one's behaviour with these laws known to the general population of what is socially acceptable is to be rude.

Similar terms include: impoliteness, making a faux pas, inconsiderateness, offensiveness, obscenity, profanity, violating taboos. In some cases, criminal behavior can also be an act of rudeness.

Cultural differences

Main: Intercultural competence

The specific actions that are considered polite or rude vary dramatically by place, time, and context. Differences in social role, gender, social class, religion, and cultural identity may all affect the appropriateness of a given behavior. Consequently, a behavior that is considered perfectly acceptable by one group of people may be considered clearly rude by another. For example, in medieval and Renaissance Europe, it was rude to indicate that a man wearing a mask in public could be recognized. Instead, polite behavior demanded that the masked person be treated as a completely unknown person and that no one ever attribute the masked person's actions to the individual who performed them. By contrast, in the modern era, greeting a friend by name while he is wearing a mask, or talking to him later about his costume or activities, is not generally considered rude.

Rudeness in Sociolinguistics Research

Instrumental Rudeness and Pragmatic Competence

In the field of linguistics research, an emphasis on the investigation and teaching of politeness has overshadowed the study of its counterpart, rudeness. Certain early seminal works in the field of linguistic pragmatics that dealt with the issue of politeness and rudeness have emphasized 'positive' aspects of conversation as being the universal norms of conversation, and saw rudeness as a defective mode of communication. More recent research has asserted that most rudeness serves functional or instrumental purposes in communication, and considers rudeness to be an important part of a person's pragmatic competence. Research in the field of pragmatic competence never really addressed common spoken rudeness and its functional aspects until the mid-1990s.

Prior to that time, most research focused on politeness and precluded the instrumental or 'useful' nature of rudeness in speech (Brown & Levinson, 1987; Grice, 1975; Lakoff, 1973). Whether it was an aberration of the "two rules" of pragmatic competence according to Lakoff (1973): (1) Be clear,(2) Be polite; or whether it violated the assumed universal norms of conversation of truthfulness, politeness and relevancy (Grice, 1975), rudeness was seen as pragmatic failure at being polite. Likewise, the politeness framework proposed in Brown and Levinson's (1987) work is also based on the idea that politeness is the norm even when employing most of the five basic strategies they identified for performing 'face-threatening acts' (FTAs; e.g., requests, complaints, refusals, etc.), acts that intrinsically threaten a speaker's public self-image (face) or that of another (Brown & Levinson, 1987, pp. 60-61). Brown and Levinson (1987) propose that talk participants choose from a hierarchy of five basic strategies for performing an FTA. Ordered from the lowest to the highest risk of face loss, they are: 1) bald, on-record; 2) positive politeness; 3) negative politeness; 4) off record; and 5) don't do the FTA (Brown & Levinson, 1987, p. 60). Talk participants are generally expected to use these politeness strategies, or 'redressive actions' (linguistic additions, modifications), in order to avoid face loss when performing an FTA. Additionally, certain variables lend a particular 'weight' to the FTA, such as power relationships between the speaker and hearer, social distance, and the rank of the imposition (Brown & Levinson, 1987, pp. 15, 74, 76-78).