Bitterness

[PussyCat]

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.

[Renato]

A feeling of deep anger and resentment. [Bitterness] is an emotion which encompasses both anger and hate, often people who are bitter appear to the world as just going around pissed off at everyone and everything. However [bitterness] is often a result of some past event which has hurt, [scarred] and [jaded] the person.

[Sommer]

1. A disease somewhat like [liberalism]
2. A rage similar to that felt by [Macho Man Randy Savage]
3. The defining aspect of [the realm]

[Dave Paprocki]

A very [unattractive] character in any person who feels the need to their emotions out on people who are usually just honest.
hard to [admit] or accept: a [bitter] lesson

[Monty]

an unpleasantly sharp taste

[Justin Bieber]

Sharpness of taste; lack of sweetness.