'Bitter' in the Bible

and the name of the star is called Wormwood: and the third part of the waters became wormwood; and many men died of the waters, because they were made bitter.

And I went unto the angel, saying unto him that he should give me the little book. And he saith unto me, Take it, and eat it up; and it shall make thy belly bitter, but in thy mouth it shall be sweet as honey.

And I took the little book out of the angel's hand, and ate it up; and it was in my mouth sweet as honey: and when I had eaten it, my belly was made bitter.