careless

形容词 careless:

1. marked by lack of attention or consideration or forethought or thoroughness; not careful
2. effortless and unstudied
3. (usually followed by `of') without due thought or consideration
   同义词：regardless

1. Careless driving kills!
   开车大意危及生命！
2. The security of the whole operation has been jeopardized by one careless person.
   整个作业的安全让一个粗心大意的人给破坏了。
3. It was most careless of me.
   我真是非常粗心。
4. You're so careless.
   你真粗心。
5. Characterized by careless ease or informality; casual.
   漫不经心的以漫不经心或随便态度为特点的; 漠不关心的
6. The careless waiter dropped the dish onto the ground.
   那个粗心的侍者把盘子摔到了地上。
7. It was careless of you to leave the door unlocked.
   你没锁门，太粗心了。
8. He is careless about his appearance.
   他不讲究外表。

care.less

adj.（形容词）
Taking insufficient care; negligent:
粗心的，疏忽的：不够当心的；忽视的：
例句：
a careless housekeeper; careless proofreading.
粗心的女管家；马马虎虎的校对

Marked by or resulting from lack of forethought or thoroughness:
轻率的：事先缺乏考虑的、不够细致周密的，由于事先缺乏考虑或不够细致周引起的：
例句：
a careless mistake.
粗枝大叶的错误

Showing a lack of consideration:
草率的，欠考虑的：
例句：
a careless remark.
草率的评论

Unconcerned or indifferent; heedless:
淡漠的：不关心的或冷淡的；不加注意的：
例句：
careless of the consequences.
不顾后果

Unstudied or effortless:
随便的：自然的或不费劲的：
例句：
danced with careless grace.
以毫不矫揉的优雅舞姿跳舞

Exhibiting a disposition that is free from cares; cheerful:
无忧无虑的：表现出轻松愉快的性情的；快活的：
例句：
a careless grin; a careless wave of the hand.
快活地咧着嘴笑；愉快的一挥手

【引伸】
care.lessly
adv.（副词）
care.lessness
n.（名词）
<参考词汇><同义词>careless,heedless,thoughtless,inadvertentThese adjectives apply to what is marked by insufficient care or attention.
这些形容词都表示不够小心谨慎的或不够注意的。
Careless often implies negligence:
Careless 经常含有疏忽的意思：
例句：
.It is natural for careless writers to run into faults they never think of. (George Berkeley).
.疏忽的作者会陷入他们从来没想到过的错误，这一点是很自然的. （乔治·贝克莱）。

Heedless suggests often reckless inattentiveness:
Heedless 常含有不顾后果的漫不经心的意思：
例句：
.We have always known that heedless self-interest was bad morals; we know now that it is bad economics. (Franklin D. Roosevelt).
.我们已经懂得，只顾草率地考虑自身利益在过去是道德败坏；我们现在知道它代表不利的经济情况. （富兰克林D·罗斯福）。

Thoughtless applies to actions taken without due thought or consideration:
Thoughtless 指没经过充分的思考或考虑而采取的行动：
例句：
.At length I recollected the thoughtless saying of a great princess, who, on being informed that the country people had no bread, replied, ‘Let them eat cake’. (Jean Jacques Rousseau).
.终于，我回忆起一位伟大的王后发表的轻率议论，她在被告知乡下人没有面包吃时回答说，‘让他们吃蛋糕吧’. （让·雅克·卢梭）。

Inadvertent is used of actions marked by unintentional lack of care:
Inadvertent 用于指不谨慎的行为，而这不谨慎是无心的：
例句：
With an inadvertent gesture she swept the vase off the table onto the floor.
她无意地做了个手势，把桌上的花瓶打翻到地上。