无名怨愤（Ressentiment）是尼采著作中的一个关键概念。来自一个法语词汇，指经济上处于低水平的阶层对经济上处于高水平的阶层普遍抱有的一种积怨。或因自卑、压抑而引起的一种愤慨。

Ressentiment (French pronunciation: ​[rəsɑ̃timɑ̃]), in philosophy and psychology, is one of the forms of resentment or hostility. It is the French word for "resentment" (fr. Latin intensive prefix 're', and 'sentir' "to feel"). Ressentiment is a sense of hostility directed at that which one identifies as the cause of one's frustration, that is, an assignment of blame for one's frustration. The sense of weakness or inferiority and perhaps jealousy in the face of the "cause" generates a rejecting/justifying value system, or morality, which attacks or denies the perceived source of one's frustration. This value system is then used as a means of justifying one's own weaknesses by identifying the source of envy as objectively inferior, serving as a defense mechanism that prevents the resentful individual from addressing and overcoming their insecurities and flaws. The ego creates an enemy in order to insulate itself from culpability.