sour

The word evokes a sharp, stinging sensation—both physically on the tongue and emotionally in the heart. It describes a transition from something pleasant or neutral to something harsh and unpleasant. In a sensory context, it is neutral but intense. Unlike 'bitter', which often feels medicinal or unpleasant, 'sour' can be desirable (like a lemon) or a sign of decay (like spoiled milk). Emotionally, it describes a specific type of negativity: resentment born from disappointment. A "sour" person isn't just angry; they are embittered, often because they feel they were treated unfairly or failed to achieve something. When used as a verb, it emphasizes the process of degradation. It suggests a slow slide into dysfunction, where a relationship or substance becomes 'spoiled' over time.