懒惰，指懈怠、好逸恶劳。有时候懒惰是因缺乏行动的欲望，而不想做任何事。怎样才被视为懒惰应依据具体的文化、社会情况及其程度而定。短暂的放松或小憩，通常是很有好处的，有助于提升个体健康指数或者摆脱亚健康状态并达成延年益寿效果的调养生息也是值得提倡的，但若是超过这种程度就变成坏处了，由于懒惰会导致生产力的下降，因此懒惰也会对社会造成问题。

虽然要到何种程度才能称懒惰，依社会而定，但在许多社会和宗教里，懒惰往往被视为道德上的罪恶，如天主教教会就将懒惰列为七宗罪之一，不过在现代医学里，感到懒散可能是忧郁症或疲劳的症状之一。

Laziness (also called indolence) is a disinclination to activity or exertion despite having the ability to act or exert oneself. It is often used as a pejorative; terms for a person seen to be lazy include couch potato, slacker, and bludger.

Despite Sigmund Freud's discussion of the pleasure principle, Leonard Carmichael notes that "laziness is not a word that appears in the table of contents of most technical books on psychology... It is a guilty secret of modern psychology that more is understood about the motivation of thirsty rats and hungry pecking pigeons as they press levers than about the way in which poets make themselves write poems or scientists force themselves into the laboratory when the good golfing days of spring arrive." A 1931 survey found that high school students were more likely to attribute their failing performance to laziness, while teachers ranked "lack of ability" as the major cause, with laziness coming in second. Laziness is not to be confused with avolition, a negative symptom of certain mental health issues such as depression, ADHD, sleep disorders, and schizophrenia.