The word "rancorous" has been used in literature to vividly evoke deep-seated bitterness and hostility, often tied to both character traits and emotional states. In Samuel Richardson’s classic, it characterizes a “little heart” as steeped in bitterness, suggesting an innate capacity for malice ([1]). Alexandre Dumas and Auguste Maquet, on the other hand, use it to mark a sort of ironic self-identification, implying that such bitterness is almost intrinsic to being a churchman ([2]). This adjective is further employed to underscore profound malevolence, as seen in the description of Alberic and Lotulf’s “malice” in Peter Abelard and Héloïse’s letters ([3]). Even in more unexpected contexts, such as Jules Verne’s portrayal of a “rancorous harpooner” ([4]), the term captures a raw, abrasive demeanor. Philosophical reflections by Arthur Schopenhauer emphasize its power to rouse “the bitterest feelings” of hatred ([5]), while Henry Fielding’s narrative describes it as the hallmark of the “worst and most rancorous kind of envy” ([6]). Through these diverse examples, "rancorous" emerges as a versatile descriptor that enriches the text with layers of emotional and moral complexity.