なにげない 英語で:

The loss resulting from careless work is very serious.

The car crashed because the driver was careless.

a careless driver

Only one careless mistake cost the company millions of dollars.

Careless as she was, she could never pass an examination.

Tatoeba: Where nothing ruins a passionate night of sentence-making like a poorly placed comma or, even worse, a careless typo.

My mother told me to do a careless job of it.

Keeping Mario in a state in which he can throw fireballs is a delicate process; that newfound power sometimes makes one cocky and careless.

Confused by her careless mistake, she burst into tears.

We shall never agree on such a careless plan.

not taking or ​showing enough ​care and ​attention: My son's ​teacher says that his ​work is often ​rather careless.

Don't be so careless about/with spelling. / a careless driver / She gave a careless shrug.

She was careless with money, so now she's in trouble financially.

If you weren't careless, your word processor wouldn't break down.

Mr Johnson was concerned about the amount of money that was being lost because of careless management.