Which word signifies a complete removal or destruction?

The word "eradicate" signifies a complete removal or destruction, making it the correct choice in this question. This term is often used in contexts where something is eliminated entirely, such as the eradication of diseases, pests, or negative influences. It conveys a strong sense of thoroughness and finality, indicating that what has been eradicated is no longer present or has been completely abolished.

In contrast, the other options do not convey the same meaning. "Eschew" refers to deliberately avoiding something, rather than removing it entirely. "Expediency" pertains to a means of achieving a particular end, often in a way that is convenient but not necessarily ethical, which doesn't relate to destruction or removal. "Fastidious" describes someone who pays great attention to detail and correctness, but it does not imply any action related to removal or destruction. Each of these terms has its own distinct meaning, which highlights why "eradicate" stands out in this context.