Absent-mindedness is where a person shows inattentive or forgetful behaviour.[20] Absent-mindedness is a mental condition in which the subject experiences low levels of attention and frequent distraction. Absent-mindedness is not a diagnosed condition but rather a symptom of boredom and sleepiness which people experience in their daily lives. When suffering from absent-mindedness, people tend to show signs of memory lapse and weak recollection of recently occurring events. This can usually be a result of a variety of other conditions often diagnosed by clinicians such as attention deficit hyperactivity disorder and depression. In addition to absent-mindedness leading to an array of consequences affecting daily life, it can have as more severe, long-term problems.
Boredom is similar to mental fatigue and is caused by repetition and lack of interest in the details of our tasks (such as tasks that require continuous attention, waiting at the airport, prisoners locked in cells). Any experience that is predictable and repetitive becomes boring. In general, too much of the same thing and too little stimulation can cause in its victim an absence of desire and a feeling of entrapment (Toohey, 2012).    
Boreout is a management theory that posits that lack of work, boredom, and consequent lack of satisfaction are a common malaise affecting individuals working in modern organizations, especially in office-based white collar jobs. This theory was first expounded in 2007 in Diagnose Boreout, a book by Peter Werder and Philippe Rothlin, two Swiss business consultants. They claim the absence of meaningful tasks, rather than the presence of stress, is many workers' chief problem.
The superfluous man (Russian: лишний человек, lishniy chelovek) is an 1840s and 1850s Russian literary concept derived from the Byronic hero.[42] It refers to an individual, perhaps talented and capable, who does not fit into social norms. In most cases, this person is born into wealth and privilege. Typical characteristics are disregard for social values, cynicism, and existential boredom; typical behaviors are gambling, drinking, smoking, sexual intrigues, and duels. He is often unempathetic and carelessly distresses others with his actions.
The most common way to define boredom in Western culture is having nothing to do. Boredom is generally viewed as an unpleasant emotional state in which the individual feels a pervasive lack of interest in and difficulty concentrating on the current activity. The condition corresponds more precisely to the French ennui, an existential perception of life’s futility. Ennui is a consequence of unfulfilled aspirations (Goodstein, 2005).