Lackadaisical

His lackadaisical attitude to studying explains his poor grades.

The company's managers had a very lackadaisical attitude towards the safety of their workers.

the lackadaisical look on his face

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.

"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."

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