Definition of "careless"

"He was here," observed Drina composedly, "and father was angry with him.""What?" exclaimed Eileen. "When?""This morning, before father went downtown."Both Selwyn and Lansing cut in coolly, dismissing the matter with a careless word or two; and coffee was served—cambric tea in Drina's case.

1907 August, Robert W[illiam] Chambers, chapter IV, in The Younger Set, New York, N.Y.: D. Appleton & Company

These ballads, none of which are later than the fifteenth century, are written in a strain of the most artless simplicity, not the slightest attempt at ornament is to be discerned in them; the same ideas and expressions continually recur, and the rimes are the most careless imaginable, often a mere assonnance in vowels or consonants, sometimes not possessing even that slight similarity of sound.

1828, Thomas Keightley, The Fairy Mythology, volume I, London: William Harrison Ainsworth, page 132

I don't find the pose of careless youth charming and engaging any more than you find the pose of careworn age fascinating and eccentric, I should imagine.

1991, Stephen Fry, The Liar, London: Heinemann, page 49

Good-humored, easy, and careless, he presided over his whale-boat as if the most deadly encounter were but a dinner, and his crew all invited guests.

1851 November 14, Herman Melville, chapter 27, in Moby-Dick; or, The Whale, 1st American edition, New York, N.Y.: Harper & Brothers; London: Richard Bentley