'Bitter' in the Bible

And the name of the star is Wormwood: and a third part of the waters became bitter; and a number of men came to their end because of the waters, for they were made bitter.

And I went to the angel, and said to him, Give me the little book. And he said to me: Put it in your mouth; and it will make your stomach bitter, but in your mouth it will be sweet as honey.

And I took the little book out of the angel's hand and did as he said; and it was sweet as honey in my mouth: and when I had taken it, my stomach was made bitter.