The term "frugality" refers to the quality of being economical with resources, often involving careful and efficient management to avoid unnecessary expenditure. To determine the correct synonym from the options provided, examine the meanings of each:
- Foolishness: The lack of good sense or judgment, which does not relate to resource management and is thus not synonymous with "frugality."
- Extremity: The furthest point or an extreme degree of something, unrelated to economical behavior.
- Enthusiasm: Intense and eager enjoyment or interest, not associated with financial management or resource conservation.
- Economy: Careful management of resources to avoid wastage, directly aligning with the meaning of "frugality."
Therefore, the word that best expresses the meaning of "frugality" is Economy.