'Bitter' in the Bible

and they made their lives bitter with hard labor in mortar and bricks and at all kinds of labor in the field, all their labors which they rigorously imposed on them.

They shall eat the flesh that same night, roasted with fire, and they shall eat it with unleavened bread and bitter herbs.

When they came to Marah, they could not drink the waters of Marah, for they were bitter; therefore it was named Marah.