Idleness

In physics, an idle machine exerts no transfer of energy. When a vehicle is not in motion, an idling engine does no useful thermodynamic work. In computing, an idle processor or network circuit is not being used by any program, application, or message.

Cultural norms

Typically, when one describes a machine as idle, it is an objective statement regarding its current state. However, when used to describe a person, idle typically carries a negative connotation, with the assumption that the person is wasting their time by doing nothing of value.

Such a view is reflected in the proverb "an idle mind is the devil's workshop". Also, the popular phrase "killing time" refers to idleness and can be defined as spending time doing nothing in particular in order that time seems to pass more quickly. These interpretations of idleness are not universal – they are more typically associated with Western cultures. Idleness was considered a disorderly offence in England punishable as a summary offense.