怠惰 (dài duò) is a formal, literary noun meaning 'idleness' or 'sloth'—a persistent lack of effort, diligence, or motivation. It carries a strong negative connotation, often implying moral or ethical failing rather than simple tiredness. The character 怠 means 'negligent' or 'lax', while 惰 means 'lazy' or 'indolent'; together, they reinforce each other to describe a deep-rooted, habitual unwillingness to work or strive.

This word appears frequently in classical texts, moral exhortations, and modern critiques of workplace or academic behavior. It is more severe than casual words like 懒 (lǎn, 'lazy') and is rarely used in light or humorous contexts. 怠惰 typically describes a person’s enduring disposition or a systemic problem—such as '怠惰之风' (a culture of idleness)—rather than a fleeting moment of laziness.