resentment

This term describes a lingering, internal state of indignation. It differs from anger in its duration and origin; while anger is often an immediate reaction, this feeling is a slow-burning bitterness that persists because the individual feels a moral or social injustice has occurred.

As an uncountable noun, it refers to the abstract emotion itself. When used to describe a specific instance of indignation or a collective reaction from a group, it remains typically uncountable, though it can occasionally be treated as countable in specific psychological or clinical contexts to denote distinct types of grievances.