Describes the act of discarding something valuable or worth saving along with something that is not needed or worthless.

Examples

"Even though the project didn't succeed, lets not throw out the baby with the bath water. We can still save much of the code we wrote"

Etymology

From a German proverb that dates to 1512. First recorded by Thomas Murner in his satire Narrenbeschwörung. First appeared in English when Thomas Carlyle translated it and used it in an 1849 essay on slavery.

Sources

Wiktionary