Resentment
Etymology
From French "ressentir," “to feel again, feel intensely,” from "re-" (again) + "sentir" (to feel), from Latin "sentire." The whole psychology is in the "re-": resentment is the injury re-felt, over and over. Each remembering re-opens the wound rather than closing it.
noun · /ri-ZENT-munt/
The lingering anger and sense of grievance over a wrong you feel was done to you.
What it names
Reach for it for anger that doesn’t discharge — a slight that gets rehearsed and nursed rather than aired or released.
Example
Years of quietly covering for her brother built into a resentment she could no longer hide.
Related idea
Against bitterness: resentment is aimed at a specific target for a specific wrong (“you did this to me”); bitterness is the diffuse, souring residue of resentments that were never resolved — it colors your whole outlook rather than pointing at one culprit. Nietzsche’s ressentiment is this feeling turned into a whole moral worldview.