'Bitter' in the Bible

and they made their lives bitter with hard service, in mortar and in brick, and in all manner of service in the field, all their service, wherein they made them serve with rigor.

And they shall eat the flesh in that night, roast with fire, and unleavened bread; with bitter herbs they shall eat it.

And when they came to Marah, they could not drink of the waters of Marah, for they were bitter: therefore the name of it was called Marah.