Which word is synonymous with being careful and cautious?

The word "prudent" is synonymous with being careful and cautious because it refers to the quality of being wise in practical matters and exercising good judgment, particularly in planning for the future. A prudent individual tends to consider potential risks and consequences before making decisions, demonstrating foresight and thoughtfulness. This aligns perfectly with the concept of carefulness and caution, making it the correct choice.

Other terms like "imprudent" actually convey the opposite meaning, as it suggests a lack of caution or care. Meanwhile, "evanescent" relates to something that fades away quickly, and "sequester" means to isolate or set apart, neither of which address the idea of being careful or cautious. Thus, "prudent" stands out clearly as the appropriate choice in this context.