In conventional usage, boredom, ennui, or tedium is an emotional and occasionally psychological state experienced when an individual is left without anything in particular to do, is listlessness and dissatisfaction arising from a lack of occupation or excitement, is not interested in their surroundings, or feels that a day or period is dull or tedious. It is also understood by scholars as a modern phenomenon which has a cultural dimension. "There is no universally accepted definition of boredom. But whatever it is, researchers argue, it is not simply another name for depression or apathy. It seems to be a specific mental state that people find unpleasant—a lack of stimulation that leaves them craving relief, with a host of behavioral, medical and social consequences." According to BBC News, boredom "...can be a dangerous and disruptive state of mind that damages your health"; yet research "...suggest[s] that without boredom we couldn't achieve our creative feats."

In Experience Without Qualities: Boredom and Modernity, Elizabeth Goodstein traces the modern discourse on boredom through literary, philosophical, and sociological texts to find that as "a discursively articulated phenomenon...boredom is at once objective and subjective, emotion and intellectualization—not just a response to the modern world, but also a historically constituted strategy for coping with its discontents." In both conceptions, boredom has to do fundamentally with an experience of time—such as experiencing the slowness of time—and problems of meaning.