'Bitter' in the Bible

They made their lives bitter by hard service with mortar and bricks and by all kinds of service in the fields. Every kind of service the Israelites were required to give was rigorous.

They will eat the meat the same night; they will eat it roasted over the fire with bread made without yeast and with bitter herbs.

Then they came to Marah, but they were not able to drink the waters of Marah, because they were bitter. (That is why its name was Marah.)