Noun
The quality or state of being bitter, sharp, or acrid, in either a literal or figurative sense; implacableness; resentfulness; severity; keenness of reproach or sarcasm; deep distress, grief, or vexation of mind.
A state of extreme impiety or enmity to God.
Dangerous error, or schism, tending to draw persons to apostasy.
Source: Webster's dictionaryBe sure to guard in your heart the joy of the Holy Spirit, and do not allow the evil one to pour out his bitterness. Beware! Beware, lest the Paradise that exists in you turns into Hell. Nectarios of Aegina
To expect too much is to have a sentimental view of life and this is a softness that ends in bitterness. Flannery O’Connor
It is hardly possible to build anything if frustration, bitterness and a mood of helplessness prevail. Lech Wałęsa
The bitterness of studying is preferable to the bitterness of ignorance. Filipino Proverb
In this world a pint of sweetness and a barrel of bitterness. Maltese Proverb
Eat the wind and swallow bitterness. Portuguese Proverb