An example of cruel is Hurricane Katrina.
The supervisor was very cruel to Josh, as he would always give Josh the hardest, most degrading work he could find.
A cruel tyrant.
Cruel treatment; a cruel remark.
He was a cruel and nasty man.
How could she have said such a cruel thing?
The ancient world was a cruel place.
Seems like it would appeal to your cruel streak of messing with people to see what they'll do.
"That's so cruel," she whispered.