'Bitterness' in the Bible

For I perceive that thou art in the gall of bitterness, and in the bond of iniquity.

Whose mouth is full of cursing and bitterness:

Let all bitterness, and wrath, and anger, and clamour, and evil speaking, be put away from you, with all malice:

Looking diligently lest any man fail of the grace of God; lest any root of bitterness springing up trouble you, and thereby many be defiled;