1 adj If you are careless, you do not pay enough attention to what you are doing, and so you make mistakes, or cause harm or damage.
oft ADJ with n (Antonym: careful)
I'm sorry. How careless of me..., Some mothers were a bit careless with money..., Mr Clarke had pleaded guilty to causing death by careless driving.
♦
carelessly adv ADV with v (Antonym: carefully)
She was fined £100 for driving carelessly...
♦
carelessness n-uncount
The defence conceded stupid goals through sheer carelessness.
2 adj If you say that someone is careless of something such as their health or appearance, you mean that they do not seem to be concerned about it, or do nothing to keep it in a good condition.
oft ADJ of/about n
He had shown himself careless of personal safety where the life of his colleagues might be at risk..., That shows a fairly careless attitude to clothes, doesn't it?