Careless
Careless是小心的反义词。如果你careful，那就意味着你做事很用心，想得很多，所以careless意味着做事没有注意或用心。
例句：
I lost points on the test due to some careless grammar mistakes.
由于一些粗心的语法错误，我在考试中丢了分。
Don't be so careless with your cell phone; you might break it.
不要对你的手机这么粗心；你可能会把它弄坏。
Carefree
This word means “free of worries and responsibilities.”
这个词的意思是没有烦恼和责任。
If you had a carefree childhood, it means you enjoyed yourself because you didn't have much stress or worry in your life. A carefree vacation would be a trip on which you stop thinking about work and other obligations.
如果你有一个carefree（无忧无虑的）童年，这意味着你生活中没有太多的压力或担心而且非常享受。一个carefree（无忧无虑的）假期就是你停止思考工作和其他义务的一段旅程。
You can also describe a person as carefree or as having a carefree attitude, meaning that their personality is the type that doesn't worry a lot.
你可以描述一个人是carefree，或者有carefree的态度，意思是他们是那种不怎么爱担心的人。
总结
Being careless is negative, it means not giving the necessary attention or thought to your wordsactions. And being carefree is positive; it means feeling nice and light, without stress, worries, or heavy obligations.
Careless是消极的，它意味着你没有对你的言行给予必要的关注或思考。而carefree是积极的；它意味着感觉很良好和轻松，没有压力，担心，或沉重的义务。
閱讀更多 英文微課堂 的文章
