They have time on their hands Crossword Clue

 The answer to the crossword clue "They have time on their hands" is CLOCKS.

This clue is a bit of a pun, as the phrase "to have time on one's hands" can mean to have nothing to do, but it can also literally mean to have hands that are telling the time. Clocks, of course, have hands that tell the time, so they are said to "have time on their hands."

Here is an example of how to use the word "clocks" in a sentence:

The old man sat in his rocking chair, watching the clocks on the mantelpiece tick by.

I hope this helps!