vacillation

This term describes a state of instability, whether mental or physical. When applied to decision-making, it carries a negative connotation of weakness or lack of resolve, suggesting a repetitive cycle of changing one's mind without reaching a conclusion. In a physical sense, it refers to the rhythmic, mechanical movement of an object. While the psychological sense is common in political or personal contexts, the physical sense is more specialized, often appearing in scientific or technical descriptions of motion.