If you say that someone is ~, you mean that they act in a way which shows that they do not care about danger or the effect their behaviour will have on other people.
He is charged with causing death by ~ driving.
ADJ
~ly
He was leaning ~ly out of the unshuttered window...
ADV: ADV with v, ADV adj
~ness
He felt a surge of ~ness...
N-UNCOUNT