Definition of "lackadaisical"

I, at one time, used to go and take a hand at cribbage with a friend, and afterwards discuss a cold sirloin of beef, and throw out a few lackadaisical remarks, in a way to please myself, but it would not do long.

1822, William Hazlitt, “On the Disadvantages of Intellectual Superiority”, in Table-Talk, volume II

"Then let those who do know it learn that you are able to bear such wounds without outward complaint. I tell you fairly that I cannot sympathize with a lackadaisical lover."

1864, Anthony Trollope, chapter 58, in The Small House at Allington

I could hear the sound of the janitor's lackadaisical scrubbing against the wooden floor.

2010, Clare Vanderpool, Moon Over Manifest