apathy — You can use apathy to talk about someone's state of mind if you are criticizing them because they do not seem to be interested in or enthusiastic about anything.
inertia — inertness, especially with regard to effort, motion, action, and the like; inactivity; sluggishness.
lethargy — the quality or state of being drowsy and dull, listless and unenergetic, or indifferent and lazy; apathetic or sluggish inactivity.
negligence — the quality, fact, or result of being negligent; neglect: negligence in discharging one's responsibilities.
sloth — habitual disinclination to exertion; indolence; laziness.
weariness — physically or mentally exhausted by hard work, exertion, strain, etc.; fatigued; tired: weary eyes; a weary brain.
dilatoriness — tending to delay or procrastinate; slow; tardy.
heaviness — of great weight; hard to lift or carry: a heavy load.
idleness — the quality, state, or condition of being lazy, inactive, or idle: His lack of interest in the larger world and his consummate idleness were the causes of their dreadful divorce.