There are many synonyms for the phrase "last quarter" that can be used to describe different time periods. One option is "final quarter," which implies that it is the last period of a specific time frame. "Fourth quarter" is another popular choice, especially in sports and business contexts, as it refers to the last three months of the year. "End of the year" is a broader synonym that can encapsulate the entire last quarter of the year, not just the final three months. Other synonyms include "year-end," "last trimester," and "end of the quarter." Ultimately, the best synonym depends on the specific time period and context being discussed.