rancor

The word rancor originates from the Latin verb rancēre, which described the state of being rank, putrid, or stinking. This literal sense of foulness was metaphorically extended in Late Latin rancor to signify a festering, deeply embedded bitterness of feeling. The term passed into Old French as rancour before entering Middle English, preserving the core concept of a persistent, unpleasant emotion. Thus, the modern abstract meaning of long-lasting resentment retains the vivid imagery of something that, like a foul odor, is pervasive and difficult to dispel.

Structure: ranc (rank, stinking) + or (noun suffix) - ranc: From Latin rancēre, meaning "to be rotten or stinking." - or: A Latin-derived noun-forming suffix indicating a state or condition.