来自短语lack a day ,来自alack the day, 哀伤的一天，alack,感伤，哀伤。引申词义无精打采的，没精神的。
英文词源
lackadaisical (adj.)
1768 (Sterne), from interjection lackadaisy "alas, alack" (1748), an alteration of lack-a-day (1690s), from alack the day (1590s). Hence, "given to crying 'lack-a-day,' vapidly sentimental." Sense probably altered by influence of lax. Related: Lackadaisically.
中文解释
缺少迪斯科就会无精打采（lack disco）
实用例句
1. Dr. Jonsen seemed a little lackadaisical at times.
琼森医生有时候似乎有点懈怠。
来自柯林斯例句
2. There'll be no time to correct lackadaisical driving techniques after trouble develops.
等到麻烦显现时再纠正动作迟缓的驾驶技术就来不及了.
来自《简明英汉词典》
3. His will was sapped and his whole attitude was lackadaisical.
心里松懈,身态与神气便吊儿啷当.
来自汉英文学 - 骆驼祥子
4. Lao Wang is very serious with work, so do not be lackadaisical.
老王干活可较真儿啦,你可别马马虎虎的.
来自互联网
5. So , Cicero first warned us against the danger of being lackadaisical.