This English expression is very commonly used, particularly in general day-to-day conversation. If you want to find out when and how to use it, read this article!
The idiom is used in order to denote the act of doing something in order to pass the time. The idea of “killing time” generally means that a person is bored and therefore spends their time doing something rather uninteresting simply to make the time pass a bit more quickly.
The first recorded use of this expression dates to 1777 in Richard Brinsley Sheridan’s, “The School for Scandal” which reads “Ay, I know there are a set of malicious, prating, prudent gossips, both male and female, who murder characters to kill time ….”
Although the idiom was used in the 18th century, it is not until the mid-19th century when it came into widespread use. It is used, for example, 3 times in “Moby Dick” by Herman Melville.
An example of the use of the expression can be found in a quote from Henry David Thoreau who is often quoted to have said “As if you could kill time without injuring eternity.”