'Bitterness' in the Bible

For I see you are poisoned by bitterness and bound by iniquity.”

Their mouth is full of cursing and bitterness.

All bitterness, anger and wrath, shouting and slander must be removed from you, along with all malice.

Make sure that no one falls short of the grace of God and that no root of bitterness springs up, causing trouble and by it, defiling many.